Flame-retardant polybutylene terephthalate resin composition and formed article

ABSTRACT

A flame-retardant polybutylene terephthalate resin composition wherein (A) 20-70% by weight of a polybutylene terephthalate resin or a mixture of a polybutylene terephthalate resin and a polyethylene terephthalate resin, (B) 1–20% by weight of a vinyl based resin, (C) 1–20% by weight of a phosphoric acid ester, (D) 1–30% by weight of a salt of a triazine based compound and cyanuric acid or isocyanuric acid, and (E) 0.1–5% by weight of an alkaline earth metal compound are compounded, and formed articles thereof have high degrees of flame retardancy and tracking resistance, and are unlikely to allow occurrence of metal pollution or deterioration in hydrolysis resistance due to a phosphoric acid ester, and therefore are suitable for machine component parts, electrical/electronic component parts, and automotive component parts.

TECHNICAL FIELD

The present invention relates to flame-retardant resin composition andformed article wherein a non-halogenated flame retardant is compoundedwith a polybutylene terephthalate resin. More particularly, theinvention relates to flame-retardant polybutylene terephthalate resincomposition and formed article which have high degree of flameretardancy, hydrolysis resistance and tracking resistance, and in whichoccurrence of metal pollution due to a phosphoric acid ester isunlikely, and which are suitable for machine mechanism component parts,electrical/electronic component parts or automotive component parts, andwhich employ a non-halogenated flame retardant.

TECHNICAL BACKGROUND

The polybutylene terephthalate resin (PBT) is utilized in a wide varietyof fields, such as machine mechanism component parts,electrical/electronic component parts, automotive component parts, etc.,making most of its excellence in characteristics, such as injectionmoldability, mechanical properties, etc.

As PBT is essentially combustible, PBTs are required to have safetyagainst flames, that is, flame retardancy, and in many cases need tohave such high degrees of flame retardancy as to indicate V-0 in the UL94 standard, as well as balance of general chemical and physicalproperties, in order to use the PBTs as industrial materials such asmachine mechanism component parts, electrical/electronic componentparts, automotive component parts, etc.

The method for imparting flame retardancy to the PBT is generally amethod in which a halogenated organic compound as a flame retardant andan antimony compound as a flame retarding assistant are compounded intoa resin. However, this method has a tendency toward large amounts ofsmoke produced during combustion.

Furthermore, with a rise of environment consciousness, there aremovements having concerns about the influences of halogenatedflame-retardant materials on the environments.

Therefore, recently, use of a flame retardant that contains none of suchhalogens has become desired.

As a method for flame-retarding a thermoplastic resin without using ahalogenated flame retardant, addition of a hydrated metallic compound,such as aluminum hydroxide, magnesium hydroxide, etc., has been widelyknown. However, the aforementioned hydrated metallic compound needs tobe added in a large amount in order to attain sufficient flameretardancy, and this method has a drawback of losing an essentialproperty of resin.

As a method for flame-retarding a thermoplastic resin without using sucha hydrated metallic compound, addition of red phosphorus is disclosed inJapanese Patent Application Laid-Open Publication No. SHO 51-150553,Japanese Patent Application Laid-Open Publication No. SHO 58-108248,Japanese Patent Application Laid-Open Publication No. SHO 59-81351,Japanese Patent Application Laid-Open Publication No. HEI 5-78560,Japanese Patent Application Laid-Open Publication No. HEI 5-287119,Japanese Patent Application Laid-Open Publication No. HEI 5-295164,Japanese Patent Application Laid-Open Publication No. HEI 5-320486,Japanese Patent Application Laid-Open Publication No. HEI 5-339417, etc.

These are useful flame-retardant resin materials not employing ahalogenated flame retardant, but have peculiar coloration so that thecolor tone of the products is limited, and therefore has the challengeof limited uses.

Furthermore, in Japanese Patent Application Laid-Open Publication No.HEI 3-281652, Japanese Patent Application Laid-Open Publication No. HEI5-70671, Japanese Patent Application Laid-Open Publication No. HEI7-233311, Japanese Patent Application Laid-Open Publication No. HEI8-73713 and Japanese Patent Application Laid-Open Publication No. HEI10-120881, compounding an aromatic phosphoric acid ester and melaminecyanurate is disclosed.

Theses are useful flame-retardant resin materials not employing ahalogenated flame retardant, but have a problem of occurrence of ableedout in which an aromatic phosphoric acid ester seeps out to aformed article surface or of bringing about metal pollution.

Furthermore, in Japanese Patent Application Laid-Open Publication No.HEI 10-77396, Japanese Patent Application Laid-Open Publication No. HEI10-147699, Japanese Patent Application Laid-Open Publication No. HEI10-182955, Japanese Patent Application Laid-Open Publication No. HEI10-182956, and Japanese Patent Application Laid-Open Publication No.2000-26710, compounding a styrene based resin into a composition inwhich a resin, such as a PBT, a polyphenylene ether, etc., and aphosphoric acid ester are compounded is disclosed.

These are useful flame-retardant resin materials not employing ahalogenated flame retardant, but have problems; for example, due to thecompounding of such a resin as a polyphenylene ether, etc., themechanical strength deteriorates, the fluidity at the time of injectionmolding deteriorates, the formed article colors yellow, and thehydrolysis resistance and the metal pollution characteristic are poor,and the uses are limited.

Furthermore, in Japanese Patent Application Laid-Open Publication No.HEI 2000-212412, compounding a polyester, and an organic phosphorusbased flame retardant including a phosphoric acid ester, as well as aglass fiber, and a vinyl based resin is disclosed.

These are useful flame-retardant resin materials not employing ahalogenated flame retardant, but have the challenge of metal pollutioncharacteristic and deterioration in hydrolysis resistance due to theorganic phosphorus based flame retardant.

Furthermore, in Japanese Patent Application Laid-Open Publication No.HEI 2001-49096, compounding a flame retardant composed of aphosphorus-containing compound including a phosphoric acid ester, andspecific aromatic resin, aromatic nylon, polycarbonate resin,polyalylate resin, polyepoxy resin and polyphenylene ether resin into aresin component including a polyester based resin and a styrene basedresin.

The aforementioned resin component including a polyester based resin anda styrene based resin is a resin component useful for improvement inmoldability related to warpage, etc., and the aforementioned flameretardant is a useful flame retardant not employing a halogenated flameretardant, but does not have effect on the challenge of the metalpollution characteristic and deterioration in hydrolyzability due to thephosphorus-containing compound.

From what is described above, although the organic phosphorus basedflame retardant, such as a phosphoric acid ester, etc., is a usefulflame retardant as a method for flame-retarding the PBT by anon-halogenated flame retardant, a flame-retardant PBT resin compositionthat does not cause the metal pollution and the deterioration inhydrolysis resistance due to a phosphoric acid ester has been desired.

Particularly, formed articles for fusers of printers and copiers,flyback transformers, focus cases, electromagnetic switches, andbreakers are often required to have excellent performance in relation tometal pollution, hydrolysis resistance and flame retardancy.

Furthermore, a phenomenon in which if voltage is applied to a formedarticle, etc., carbonization of the formed article progresses andresults in ignition is termed tracking. Many formed articles of the PBTare used under high voltage modification. For example, as for theaforementioned formed articles for fusers of printers and copiers,electromagnetic switches, and breakers, etc., formed articles havingexcellent flame retardancy and a relative tracking index of 400V orhigher, and preferably 600V or higher, are desired.

It would therefore be advantageous to attain highly reliableflame-retardant polybutylene terephthalate resin composition and formedarticle in which a non-halogenated flame retardant is compounded with apolybutylene terephthalate resin, and which have high degrees of flameretardancy and tracking resistance, and which are unlikely to allowoccurrence of metal pollution or deterioration in hydrolysis due to aphosphoric acid ester.

SUMMARY OF THE INVENTION

A flame-retardant polybutylene terephthalate resin composition isprovided wherein (A) 20–70% by weight of a polybutylene terephthalateresin or a mixture of a polybutylene terephthalate resin and apolyethylene terephthalate resin, (B) 1–20% by weight of a vinyl basedresin, (C) 1–20% by weight of a phosphoric acid ester, (D) 1–30% byweight of a salt of a triazine based compound and cyanuric acid orisocyanuric acid, and (E) 0.1–5% by weight of an alkaline earth metalcompound are compounded, and formed articles made of the flame-retardantpolybutylene terephthalate resin composition so as to be used as machinemechanism component parts, electrical/electronic component parts orautomotive component parts.

DETAILED DESCRIPTION

The (A) polybutylene terephthalate resin is a polymer obtained by apolycondensation reaction of terephthalic acid or its ester-formingderivative and 1,4-butanediol or its ester-forming derivative; besides,isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacicacid, dodecanedioic acid, oxalic acid, etc., as an acid component, andethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol,1,6-hexanediol, decamethylene glycol, cyclohexanedimethanol,cyclohexanediol, etc., or a long chain glycol having a molecular weightof 400–6000, namely, polyethylene glycol, poly-1,3-propylene glycol,polytetramethylene glycol, etc., as a glycol component, may becopolymerized at 20 mol % or less. As preferable examples of the polymeror copolymer, polybutylene terephthalate,polybutylene(terephthalate/isophthalate),polybutylene(terephthalate/adipate),polybutylene(terephthalate/sebacate),polybutylene(terephthalate/decanedicarboxylate),polybutylene(terephthalate/naphthalate), etc., may be cited, which maybe used singly or used in a mixture of two or more species thereof.Incidentally, “/” herein means copolymerization.

Furthermore, as for the polymer or copolymer, the ones whose intrinsicviscosity measured at 25° C. by using an o-chlorophenol solvent iswithin the range of 0.36–1.60 and particularly of 0.42–1.25 is preferredin view of the impact strength and moldability of the resultantcompositions. Furthermore, as for the (A) polybutylene terephthalateresin, poly-butylene terephthalate resins different in intrinsicviscosity may be used together. It is preferable to use polybutyleneterephthalate resins whose intrinsic viscosity is within the range of0.36–1.60.

Still further, as for such polybutylene terephthalate resins, the oneswhose COOH terminal group amount determined by potentiometric titrationof an m-cresol solution with an alkali solution is within the range of1–50 eq/t (terminal group amount in 1 ton of polymer) are preferablyused in view of durability. In particular, the ones whose COOH terminalgroup amount is 45 eq/t or less, and more preferably 30 eq/t or less,and more preferably 20 eq/t or less are preferably used since they areexcellent in hydrolysis resistance.

Furthermore, the polyethylene terephthalate resin of the mixture of thepoly-ethylene terephthalate resin and the polybutylene terephthalateresin component of the (A) component in the present invention refers toa high-molecular weight thermoplastic polyester resin in which a mainchain formed through a polycondensation using terephthalic acid as anacid component and ethylene glycol as a glycol component has esterlinkages; besides, isophthalic acid, adipic acid, oxalic acid, etc., asan acid component, and propylene glycol, 1,4-butanediol, neopentylglycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol,cyclohexanedimethanol, cyclohexanediol, etc., or a long chain glycolhaving a molecular weight of 400–6000, namely, polyethylene glycol,poly-1,3-propylene glycol, polytetramethylene glycol, etc., as a glycolcomponent, may be copolymerized at 20 mol % or less. Furthermore, as forthe polyethylene terephthalate resin, the ones whose intrinsic viscositymeasured at 25° C. by using an o-chlorophenol solvent is within therange of 0.36–1.60 and particularly of 0.45–1.15 is preferred in view ofthe impact strength and moldability of the resultant compositions.

Furthermore, with regard to the mixing proportion with the polybutyleneterephthalate resin that forms the (A) component, the polybutyleneterephthalate resin is at 5–95% by weight and the polyethyleneterephthalate resin is at 95–5% by weight in view of flame retardancyand crystallinity; more preferably, the polybutylene terephthalate resinis at 25–75% by weight and the polyethylene terephthalate resin is at75–25% by weight.

Furthermore, the compounding amount of the polybutylene terephthalateresin or the mixture of a polybutylene terephthalate resin and apolyethylene terephthalate resin that forms the (A) component is 20–70%by weight, more preferably 20–65% by weight, and particularly preferably25–60% by weight.

Furthermore, one or more species of polyester resins, such as apolyalylate resin, a full aromatic liquid crystal polyester, asemi-aromatic liquid crystal polyester, a polycyclohexandimethyleneterephthalate resin, etc., may be compounded with the (A) component, andthe compounding amount thereof is an amount within such a range that theeffects are not considerably reduced.

As the (B) vinyl based resin, a resin made by polymerizing one or morespecies of monomers selected from aromatic vinyl compounds, vinylcyanide compounds, (meth)acrylic acid alkyl esters and maleimide basedmonomers, or a one made by graft-polymerizing or copolymerizing suchmonomers with a rubber based component, such as a polybutadiene basedrubber, etc., etc., may be cited (hereinafter, these resins willsometimes be collectively referred to as “(co)polymer”) although the (B)vinyl based resin is not limited thereto.

As the aforementioned aromatic vinyl compound, styrene, α-methylstyrene, vinyltoluene, divinyl benzene, etc., may be cited. As the vinylcyanide compound, acrylonitrile, methacrylonitrile, etc., may be cited.As the (meth)acrylic acid alkyl ester, (meth)acrylic acid alkyl esters,such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate,methyl acrylate, ethyl acrylate, n-butyl acrylate, stearyl acrylate,etc. may be cited. As the maleimide based monomer, maleimide,N-substituted maleimides, such as N-methyl maleimide, N-ethyl maleimide,N-phenyl maleimide, N-cyclohexyl maleimide as well as their derivatives,etc., etc., may be cited. Furthermore, vinyl based resins with abelow-mentioned component being copolymerizable with the aforementionedvinyl based resin are also included in the present invention. Asspecific examples of the aforementioned copolymerizable component, dienecompounds, maleic acid dialkyl esters, allyl alkyl ethers, unsaturatedamino compounds, vinyl alkyl ethers, etc., may be cited.

As examples of preferable (co)polymers of the (B) vinyl based resin,vinyl based (co)polymers, such as polymethyl methacrylate resins, methylmethacrylate/acrylonitrile resins, polystyrene resins,acrylonitrile/styrene resins (AS resins), styrene/butadiene resins,styrene/N-phenyl maleimide resins, styrene/acrylonitrile/N-phenylmaleimide resins, etc., styrene based resins modified by gum polymers,such as acrylonitrile/butadiene/styrene resins (ABS resins),acrylonitrile/butadiene/methyl methacrylate/styrene resins (MABSresins), high-impact polystyrene resins, etc., andstyrene/butadiene/styrene resins, styrene/isoprene/styrene resins,styrene/ethylene/butadiene/styrene resins, etc., as block copolymers,may be cited. In particular, polystyrene resins andacrylonitrile/styrene resins are preferable. Furthermore,acrylonitrile/styrene copolymer, which is a copolymer made bycopolymerizing acrylonitrile and styrene, are more preferable(/indicates copolymerization).

Furthermore, as for the acrylonitrile/styrene copolymer,acrylonitrile/styrene copolymers containing acrylonitrile at 10 wt. % orgreater and less than 50 wt. % are particularly preferable. Morepreferably, the content of acrylonitrile is 20 wt. % or greater and lessthan 40 wt. %. If the content of acrylonitrile is within an appropriaterange, the employment thereof together with an alkali metal compoundachieves particularly increased effects of enhancing hydrolysisresistance and improving metal pollution characteristic.

Furthermore, an acrylonitrile/styrene copolymer containing acrylonitrileat 10 wt. % or greater and less than 50 wt. % may be copolymerized withother copolymerizable monomers within such a range that the effects willnot be impaired. As the copolymerizable monomers, aromatic vinylcompounds, (meth)acrylic acid alkyl esters, maleimide based monomers,etc., may be cited; specifically, the foregoing compounds may be cited.

Furthermore, the vinyl based resin may be a vinyl based copolymer inwhich unsaturated monocarboxylic acids and the like, unsaturateddicarboxylic acids and the like, unsaturated acid anhydrides, or epoxygroup-containing vinyl based monomers are graft-polymerized orcopolymerized.

In particular, the copolymer is preferably a vinyl based copolymer inwhich unsaturated acid anhydrides or epoxy group-containing vinyl basedmonomers are graft-polymerized or copolymerized.

The epoxy group-containing vinyl based monomers as mentioned above arecompounds that have in one molecule both an epoxy group and a vinylgroup capable of radical polymerization. As specific examples thereof,glycidyl esters and the like of unsaturated organic acids, such asglycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidylitaconate, etc., glycidyl ethers and the like, such as allyl glycidylethers, etc., and derivatives and the like of the aforementionedmonomers, such as 2-methyl glycidyl methacrylate, etc., may be cited. Inparticular, glycidyl acrylate and glycidyl methacrylate may bepreferably used. These may also be used singly or in a combination ortwo or more species.

Furthermore, the unsaturated acid anhydrides and the like are compoundshaving in one molecule both an acid anhydride and a vinyl group capableof radical polymerization. As specific examples thereof, maleicanhydride, etc. may be preferably cited.

As for the method for producing the vinyl based copolymer in which theaforementioned unsaturated monocarboxylic acids and the like, theunsaturated dicarboxylic acids and the like, the unsaturated acidanhydrides, or the epoxy group-containing vinyl based monomers aregraft-polymerized or copolymerized, ordinarily known methods may beadopted. Particularly, a method in which an aromatic vinyl monomer(preferably, styrene), or an aromatic vinyl monomer (preferably,styrene) and another monomer copolymerizable with the foregoing monomerare copolymerized with an unsaturated monocarboxylic acid or the like,an unsaturated dicarboxylic acid or the like, an unsaturated acidanhydride, or an epoxy group-containing vinyl based monomer, a method inwhich the aforementioned (co)polymer is graft-polymerized with anunsaturated monocarboxylic acid or the like, an unsaturated dicarboxylicacid or the like, an unsaturated acid anhydride, or an epoxygroup-containing vinyl based monomer may be cited. The copolymerizationand graft polymerization as mentioned above may be carried out by knownmethods as well.

The amount of an unsaturated monocarboxylic acid or the like, anunsaturated dicarboxylic acid or the like, an unsaturated acidanhydride, or an epoxy group-containing vinyl based monomer used for thegraft polymerization or the copolymerization is not particularly limitedas long as it is effective in improving the compatibility between the(A) component and the vinyl based resin. However, it is preferable thatthe amount thereof be 0.05% by weight or greater with respect to thevinyl based resin. If a large amount thereof is copolymerized, there isa tendency toward fluidity deterioration or gelation. Therefore, theamount is preferably 20% by weight or less, more preferably 10% byweight or less, and more preferably 5% by weight or less.

Furthermore, the vinyl based (co)polymer may also be a vinyl based(co)polymer in which the (co)polymer mentioned above is epoxy-modifiedwith an epoxidizing agent, such as a peroxide or the like, performicacid, peracetic acid, perbenzoic acid, etc. In this case, in order toeffectively bring about the epoxy modification, it is preferable thatthe vinyl based resin be random-copolymerized or block-copolymerizedwith a diene based monomer. As for examples of the diene based monomer,butadiene, isoprene, etc., are preferably used. Examples of preferredproduction methods for the epoxy-modified vinyl based resins areindicated in Japanese Patent Application Laid-Open Publication No. HEI6-256417, Japanese Patent Application Laid-Open Publication No. HEI6-220124, etc. As preferable vinyl based resins, copolymers, such asstyrene/butadiene resins, etc., ABS based resins, such asacrylonitrile/butadiene/styrene resins (ABS resins),acrylonitrile/butadiene/methyl methacrylate/styrene resins (MABSresins), etc., block copolymers, such as styrene/butadiene/styreneresins, styrene/butadiene resins, styrene/isoprene/styrene resins,styrene/ethylene/butadiene/styrene resins, etc., may be cited. Amongthese, block copolymers, such as styrene/butadiene/styrene resins,styrene/isoprene/styrene resins, styrene/ethylene/butadiene/styreneresins, etc., are preferably used.

Furthermore, the amount of the epoxy group introduced into the vinylbased resin in an epoxy group introduction method using an epoxidizingagent is not particularly limited as long as it is effective inimproving the compatibility between the (A) component and the vinylbased resin. However, the epoxy equivalent thereof is preferably 100g/equivalent or greater and 10000 g/equivalent or less, more preferably200 or greater and 5000 g/equivalent or less, and more preferably 250 orgreater and 3000 g/equivalent or less. The epoxy equivalents of theresins can be measured by a method described in Japanese PatentApplication Laid-Open Publication No. HEI 6-256417.

Vinyl based resins in which epoxy group-containing vinyl based monomersare graft-polymerized or copolymerized, and block copolymersepoxy-modified by an epoxidizing agent, such asstyrene/butadiene/styrene resins, styrene/isoprene/styrene resins,styrene/ethylene/butadiene/styrene resins, etc., are preferably used asdue to good compatibility with the (A) component. Moreover, vinyl basedresins in which glycidyl methacrylate is graft-polymerized orcopolymerized are more preferably used. In particular, ones in whichglycidyl methacrylate is copolymerized are preferable, and copolymers inwhich styrene, acrylonitrile and glycidyl methacrylate are copolymerizedare particularly preferable. The preferable amount of glycidylmethacrylate copolymerized in the aforementioned copolymer in whichstyrene, acrylonitrile and glycidyl methacrylate are copolymerized ispreferably an amount that is effective in improving the compatibilitywith the (A) component. It is preferable that the amount be 0.1% byweight or greater with respect to the copolymer. If a large amountthereof is copolymerized, there is a problem of fluidity deteriorationor gelation. Therefore, the amount is preferably 20% by weight or less,more preferably 10% by weight or less, and more preferably 5% by weightor less. Furthermore, there are no particular restrictions on theamounts of styrene and acrylonitrile copolymerized. However, withrespect to the total of styrene and acrylonitrile, acrylonitrile ispreferably at 10% by weight or greater and 50% by weight or less, andmore preferably at 20% by weight or greater and 40% by weight or less.

Furthermore, as a preferable one of the (B) vinyl based resin, amultilayer structure made up of an innermost layer (core layer) and anouter layer (shell layer) covering the innermost layer wherein the outerlayer (shell layer) is composed of a vinyl based resin may be cited.This multilayer structure is a polymer having a structure that isgenerally termed core-shell form and that is formed by an innermostlayer (core layer) and one or more species of outer layers (shelllayers) covering the innermost layer, wherein the (B) vinyl based resinis formed as a species of the outer layers (shell layers), andcontiguous layers are composed of different species of polymers.

The number of layers that compose the multilayer structure is notparticularly limited. It is appropriate that the number of layers be 2or greater. The number of layers may also be 3 or greater, or 4 orgreater.

Furthermore, the multilayer structure is preferably a multilayerstructure having therein at least one rubber layer.

In the multilayer structure, the kind of the rubber layer is notparticularly limited, but it is appropriate that the rubber layer becomposed of a polymer component having rubber elasticity. For example,rubbers composed of polymerized products of an acryl component, asilicone component, a styrene component, a nitrile component, aconjugated diene component, a urethane component, an ethylene propylenecomponent, etc. may be cited. Preferable rubbers, for example, arerubbers composed of polymerized products of acryl components, such asethyl acrylate units, butyl acrylate units, etc., silicone components,such as dimethylsiloxane unit, phenylmethylsiloxane units, etc., styrenecomponents, such as styrene units, α-methyl styrene units, etc., nitrilecomponents, such as acrylonitrile units, methacrylonitrile units, etc.,and conjugated diene components, such as butanediene units, isopreneunits, etc. Furthermore, rubbers composed of copolymerized products ofcombinations of two or more species of these components are alsopreferable. For example, (1) rubbers composed of components in whichacryl components, such as ethyl acrylate units, butyl acrylate units,etc., and silicone components, such as dimethylsiloxane units,phenyl-methylsiloxane units, etc., are copolymerized, (2) rubberscomposed of components in which acryl components, such as ethyl acrylateunits, butyl acrylate units, etc., and styrene components, such asstyrene units, α-methyl styrene units, etc., are copolymerized, (3)rubbers composed of components in which acryl components, such as ethylacrylate units, butyl acrylate units, etc., and conjugated dienecomponents, such as butanediene units, isoprene units, etc., arecompounded, and (4) rubbers composed of components in which acrylcomponents, such as ethyl acrylate units, butyl acrylate units, etc.,silicone components, such as dimethylsiloxane units, phenylmehtylsioxaneunits, etc., and styrene components, such as styrene units, α-methylstyrene units, etc., are copolymerized, etc. may be cited. Furthermore,besides the aforementioned components, rubbers in which crosslinkablecomponents, such as divinylbenzene units, allyl acrylate units, butyleneglycol diacrylate units, etc., are copolymerized and crosslinked arealso preferable.

In the multilayer structure, the core layer is composed of a vinyl basedresin, and is preferably a polymer component having a higher glasstransition temperature than the rubber layer. As a vinyl based resinthat composes the core layer, polymers containing at least a vinyl basedresin of one or more species of units selected from an unsaturatedcarboxylic acid alkyl ester based unit, an unsaturated glycidylgroup-containing unit, an unsaturated dicarboxylic anhydride based unit,an aliphatic vinyl based unit, an aromatic vinyl based unit, a vinylcyanide based unit, a maleimide based unit, an unsaturated dicarboxylicacid based unit, and other vinyl based units, etc., may be cited. Inparticular, polymers containing at least one species of units selectedfrom the aliphatic vinyl based unit, the unsaturated carboxylic acidalkyl ester based unit, the unsaturated glycidyl group-containing unit,and the unsaturated dicarboxylic anhydride based unit are preferable.

Although the unsaturated carboxylic acid alkyl ester based unit is notparticularly limited, (meth)acrylic acid alkyl esters are preferablyused. Specifically, methyl (meth)acrylate, ethyl (meth)acrylate,n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate,n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl(meth)acrylate, stearyl (meth)acrylate, octadecyl (meth)acrylate, phenyl(meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,3-hydroxypropyl (meth)acrylate, 2,3,4,5,6-pentahydroxyhexyl(meth)acrylate, 2,3,4,5-tetrahydroxypentyl (meth)acrylate, aminoethylacrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate,ethyl aminopropyl methacrylate, phenylaminoethyl methacrylate,cyclohexylaminoethyl methacrylate, etc., may be cited, and methyl(meth)acrylate is preferably used. These units may be used singly or twoor more species thereof may be used together.

Furthermore, the aforementioned unsaturated glycidyl group-containingunit is not particularly limited, and glycidyl (meth)acrylate, glycidylitaconate, diglycidyl itaconate, allyl glycidyl ether,styrene-4-glycidyl ether, 4-glycidyl styrene, etc., may be cited. Inview of the great effect of improving the impact resistance, glycidyl(meth)acrylate is preferably used. These units may be used singly or twoor more species thereof may be used.

Furthermore, as the aforementioned unsaturated dicarboxylic anhydridebased unit, maleic anhydride, itaconic anhydride, glutaconic anhydride,trimellitic anhydride, pyromellitic anhydride, etc., may be cited. Inview of the great effect of improving the impact resistance, maleicanhydride is preferably used. These units may be used singly or two ormore species thereof may be used.

Furthermore, as the aforementioned aromatic vinyl based unit, styrene,α-methyl styrene, 1-vinylnaphthalene, 4-methyl styrene, 4-propylstyrene,4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene,4-(phenylbutyl)styrene, etc. may be cited. As the aforementioend vinylcyanide based unit, acrylonitrile, methacrylonitrile, ethacrylonitrile,etc. may be cited. As the aformentioned maleimide based unit, maleimide,N-methyl maleimide, N-ethyl maleimide, N-propylmaleimide,N-isopropylmaleimide, N-cyclohexylmaleimide, N-phenyl maleimide, etc.may be cited. As the aformentioned unsaturated dicarboxylic acid basedunit, maleic acid, maleic acid monoethyl ester, itaconic acid, phthalicacid, etc. may be cited. As the aforementioned other vinyl based units,acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide,N-propylmethacrylamide, N-vinyl diethylamine, N-acetylvinylamine,allylamine, methallyamine, N-methylallylamine, p-aminostyrene,2-isopropeny-oxazoline, 2-vinyl-oxazoline, 2-acroyl-oxazoline,2-styryl-oxazoline, etc. may be cited. These units may be used singly ortwo or more species thereof may be used together. Acrylonitrile/styrenecopolymers made up of aromatic vinyl based units and vinyl based unitsare preferably used.

Furthermore, as preferable examples of the multilayer structure, ones inwhich the core layer is of a dimethylsiloxane/butyl acrylate polymer andthe outermost layer is of a methyl methacrylate or anacrylonitrile/styrene copolymer, ones in which the core layer is of abutanediene/styrene polymer and the outermost layer is of a methylmethacrylate polymer or an acrylonitrile/styrene copolymer, ones inwhich the core layer is of a butyl acrylate polymer and the outermostlayer is of a methyl methacrylate polymer or an acrylonitrile/styrenecopolymer, etc. may be cited. Still further, it is more preferable thatone or both of the rubber layer and the outermost layer be of a polymercontaining glycidyl methacrylate units.

Furthermore, the particle diameter of the multilayer structure is notparticularly limited, but it is preferable that the particle diameterthereof be 0.01 μm or greater and 1000 μm or less, and furthermore, itis more preferable that it be 0.02 μm or greater and 100 μm or less, andparticularly, it is most preferable that it be 0.05 μm or greater and 10μm or less.

Furthermore, the weight ratio between the core and shell in themultilayer structure is not particularly limited, but it is preferablethat the core layer be at 10% by weight or greater and 90% by weight orless with respect to the entire multilayer structure, and it is morepreferable that it be 30% by weight or greater and 80% by weight orless.

Furthermore, as for the multilayer structure, a commercially sold itemthat meets the foregoing conditions may be used, or a multilayerstructure may be prepared by a known method so as to be used.

Furthermore, as for the commercially sold items of the multilayerstructure, “Metablen” produced by Mitsubishi Rayon Co., “Kane Ace”produced by Kanegafuchi Kagaku Kogyo Co., “Paraloid” produced by KurehaChemical Industry Co., “Acryloid” by Rohm & Haas Co., “Staphyloid”produced by Takeda Pharmaceutical Co., “Parapet SA” produced by KurarayCo., etc. may be cited. These may be used singly or two or more speciesthereof may be used together.

Furthermore, the compounding amount of the (B) vinyl based resin may be1–20% by weight, more preferably 2–18% by weight, and particularlypreferably 2–15% by weight in view of the flame retardancy, the contactcontamination characteristic improving effect, and the hydrolysisresistance enhancing effect of the resultant flame-retardant resincomposition caused by the combined use with other components.

The (C) phosphoric acid ester is not particularly limited, but generallycommercially sold items or synthesized phosphoric acid esters may beused. As specific examples, tricresyl phosphate, trixylenyl phosphate,cresyldiphenyl phosphate, triphenyl phosphate, tris-isopropylbiphenylphosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate,trioctyl phosphate, tributoxyethyl phosphate, octyldiphenyl phosphate,orthophenyl phenol based phosphoric acid ester, pentaerythritol basedphosphoric acid ester, neopentylglycol based phosphoric acid ester,substituted neopentylglycol phosphonate, nitrogenated based phosphoricacid ester, the aromatic phosphoric acid esters of the followingexpression (1), etc. may be cited. Particularly, the aromatic phosphoricacid esters of the following expression (1) are preferably used.

(In the above expression, Ar¹, Ar², Ar³ and Ar⁴ represent the same ordifferent aromatic groups that do not contain a halogen. Furthermore, Xrepresents a structure selected from the following expressions (2)–(4).In the following expressions (2)–(4), R¹–R⁸ represent the same ordifferent hydrogen atoms or alkyl groups having carbon numbers of 1–5, Yrepresents a direct coupling, O, S, SO₂, C(CH₃)₂, CH₂, CHPh, and Phrepresents a phenyl group. Furthermore, n in the (1) expression is aninteger of 0 greater. Furthermore, k, m in the (1) expression are eachan integer of 0 or greater and 2 or less, and (k+m) is an integer of 0or greater and 2 or less.) Incidentally, the aromatic phosphoric acidester may be a mixture of aromatic phosphoric acid esters havingdifferent integers n and different structures.

More specifically, n in the expression of the expression (1) is aninteger of 0 or greater, and the upper limit thereof is preferably 40 orless in view of flame retardancy. The integer n is preferably 0–10, andparticularly preferably 0–5.

Furthermore, k, m are each an integer of 0 or greater and equal 2 orless, and k+m is an integer of 0 or greater and 2 or less. Preferably,k, m are each an integer of 0 or greater and 1 or less, and morepreferably, k, m are each 1.

Furthermore, in the expressions of the expressions (2)–(4), R¹–R⁸represent the same or different hydrogen atoms or alkyl groups havingcarbon numbers of 1–5. As specific examples of the alkyl groups havingcarbon numbers of 1–5, methyl group, ethyl group, n-propyl group,isopropyl group, n-butyl group, sec-butyl group, tert-butyl group,n-isopropyl, neopentyl, tert-pentyl group, 2-isopropyl, 3-isopropyl,neoisopropyl, etc. may be cited. Hydrogen, methyl group, and ethyl groupare preferable, and hydrogen is particularly preferable.

Furthermore, Ar¹, Ar², Ar³ and Ar⁴ represent the same or differentaromatic groups that do not contain a halogen. As the aromatic groupsmentioned above, aromatic groups having a benzene skeleton, anaphthalene skeleton, an indene skeleton, an anthracene skeleton may becited. In particular, ones having a benzene skeleton or a naphthaleneskeleton are preferable. These may be substituted by an organic residuethat does not have a halogen (preferably an organic residue having acarbon number of 1–8). The number of substituted groups is notparticularly limited, but its preferable that the number thereof be 1–3.As specific examples, aromatic groups, such as phenyl group, tolylgroup, xylyl group, cumenyl group, mesityl group, naphthyl group,indenyl group, anthryl group, etc., may be cited. Phenyl group, tolylgroup, xylyl group, cumenyl group, and naphthyl group are preferable,and phenyl group, tolyl group, and xylyl group are particularlypreferable.

In particular, the following compounds (6), (7) are preferable, and the(6) compound is particularly preferable.

As for commercially sold phosphoric acid esters, one species or two ormore species selected from PX-200, PX-201, PX-130, CR-733S, TPP, CR-741,CR747, TCP, TXP and CDP produced by Daihachi Kagaku Co. may be used, andpreferably one species or two or more species selected from PX-200, TPP,CR-733S, CR-741 and CR747 may be used, and particularly preferablyPX-200, CR-733S and CR-741 may be used. Among these, PX-200 is the mostpreferable because the effect of improving the hydrolysis resistance andthe contact contamination characteristic is particularly great in thecases of combined use with a vinyl based resin and an alkaline earthmetal compound.

Furthermore, the adding amount of the (C) phosphoric acid ester is 1–20%by weight, preferably 2–18% by weight, and more preferably 3–15% byweight in view of flame retardancy, hydrolysis resistance, and metalpollution.

As for the salt of the (D) triazine based compound with cyanuric acid orisocyanuric acid, the adduct between cyanuric acid or isocyanuric acidand a triazine based compound is preferable, and is an adduct having acomposition of ordinarily 1-1 (molar ratio) and sometimes 1-2 (molarratio). Of the triazine based compounds, ones that do not form a saltwith cyanuric acid or isocyanuric acid are excluded. Furthermore, amongthe salts of the (D) triazine based compound and cyanuric acid orisocyanuric acid, salts of melamine, benzoguanamine, acetoguanamine,2-amide-4,6-diamino-1,3,5-triazine, mono(hydroxymethyl)melamine,di(hydroxymethyl)melamine and tri(hydroxymethyl)melamine are preferable,and particularly salts of melamine, benzoguanamine and acetoguanamineare preferable. They are produced by known methods. For example, amixture of a triazine based compound and cyanuric acid or isocyanuricacid is prepared as water slurry, and is thoroughly mixed so that thesalt of the two substances is formed as fine particles, and then theslurry is filtered and dried, so that the salt is generally obtained ina powder form. Furthermore, the aforementioned salt does not need to becompletely pure but small amounts of unreacted triazine based compoundor cyanuric acid or isocyanuric acid may remain therein. Furthermore,the number average particle diameter of the salt prior to thecompounding into the resin is preferably 100-0.01 μm, and morepreferably 80-1 μm, in view of the flame retardancy, mechanicalstrength, moist heat resistance characteristic, residence stability,surface characteristic of the formed article. Furthermore, if thedispersion of the salt is poor, a dispersing agent, such astris(β-hydroxy-ethyl)isocyanurate, etc., or a known surface treatingagent, etc., may well be used together.

Furthermore, the compounding amounts of the salt of the (D) triazinebased compound and cyanuric acid or isocyanuric acid is 1–30% by weight,preferably 2–25% by weight, and particularly preferably 3–20% by weight,in view of flame retardancy and mechanical characteristic.

As the alkaline earth metal in the (E) alkaline earth metal compound,magnesium, calcium, barium, etc., are preferably cited. Furthermore, asthe alkaline earth metal compound, hydroxides, oxides, inorganic acidsalts, such as carbonic acid salts, sulfuric acid salts, acetic acidsalts, phosphoric acid salts, etc., and organic acid salts, such asacetic acid salts, lactic acid salts, oleic acid, palmitic acid, stearicacid, montanoic acid, etc. are preferable. As specific examples,magnesium hydroxide, calcium hydroxide, barium hydroxide, magnesiumoxide, calcium oxide, barium oxide, magnesium carbonate, calciumcarbonate, barium carbonate, magnesium sulfate, calcium sulfate, bariumsulfate, magnesium phosphate, calcium phosphate, barium phosphate,magnesium acetate, calcium acetate, barium acetate, magnesium lactate,calcium lactate, barium lactate, and, furthermore, magnesium salts,calcium salts, barium salts, etc. of organic acids, such as oleic acid,palmitic acid, stearic acid, montanoic acid, etc., may be cited. Amongthese, hydroxides and carbonic acid salts of alkaline earth metals arepreferably used. Particularly, magnesium hydroxide and calcium carbonateare preferably used, and more preferably, calcium carbonate is used.Such alkaline earth metals may be used in a fashion of one species ortwo or more species. Furthermore, as for the aforementioned calciumcarbonate, cololide calcium carbonate, precipitated calcium carbonate,ground calcium carbonate, levigated fine powder ground calciumcarbonate, wet ground calcium carbonate (chalk), etc., according to theproduction methods, are known, and each one of them is encompassed inthe present invention.

These alkaline earth metal compounds may be treated with one or morespecies of surface treating agents, such as silane coupling agents,organic substances, inorganic substances, etc. The configuration thereofmay be a powder form, a platy form, or a fibrous form. However, it ispreferable to use the alkaline earth metal compound in the form of apowder of 10 μm or less in view of dispersibility, etc. If the particlediameter is even smaller, the effect of enhancing the hydrolysisresistance is great, and therefore smaller particle diameters arepreferable.

By adding the (E) alkaline earth metal compound, the hydrolysischaracteristic can be remarkably enhanced, due to the combined use withthe (B) vinyl based resin. The phosphoric acid ester based compoundeffective as a non-halogenated flame retardant has a drawback of beinginferior in hydrolysis resistance since the phosphoric acid esterlinkage is easily hydrolyzable. By using the vinyl based resin and thealkaline earth metal compound in a combined use fashion, very higheffect of enhancing hydrolysis resistance and improving metal pollutioncharacteristic can be obtained. It is speculated that the very higheffect is obtained due to the acid trap by the alkaline earth metal, andthe prevention of elusion of the phosphoric acid ester by the additionof a vinyl compound having high affinity to the phosphoric acid ester.

It is generally known that the hydrolysis of polyesters is acceleratedby an acid or an alkali serving as a catalyst. Alkali metal compoundshave alkalinity in many cases, and accelerates the hydrolysis ofpolyesters in ordinary cases. Therefore, addition thereof is notpreferable. Therefore, as for the alkaline earth metal compound, onesthat are hardly soluble in water if in a neutral state, and thatdissolves in an environment acidization and exhibits a neutralizingaction if the phosphoric acid ester decomposes so that the systembecomes acidic, are preferably used. The solubilities in the neutralstate are described in various handbooks, for example, ChemicalHandbook, published (1966) by Maruzen Kabushikigaisha, etc. Thesolubility in water is preferably 1 g/100 g water, more preferably 10⁻¹g/100 g water, and particularly preferably 10⁻² g/100 g water.Incidentally, the solubility in water of calcium carbonate, which ismost preferably used, is 5.2×10⁻³ g/100 g water.

Furthermore, the compounding amount of the (E) alkaline earth metalcompound is 0.1–5% by weight, preferably 0.2–4% by weight, and morepreferably 0.3–3% by weight, in view of mechanical characteristic andhydrolysis resistance.

Furthermore, as for the compounding amount of the (E) alkaline earthmetal compound, it is particularly preferable that the compounding ratiobetween the (C) phosphoric acid ester and the (E) alkaline earth metalcompound be as in the following expression (5).

$\begin{matrix}{{\frac{Wp}{M} \times {Np} \times 0.03} \leqq {\frac{Wa}{Ma} \times 2} \leqq {\frac{Wp}{M} \times {Np} \times 0.6}} & (5)\end{matrix}$

-   -   (In the above expression, Wp represents the compounding amount        of the (C) phosphoric acid ester (% by weight), M represents the        molecular weight of the (C) phosphoric acid ester, Np represents        the number of phosphoric acid ester linkages of the phosphoric        acid ester of (C), Wa represents the compounding amount of        the (E) alkaline earth metal compound (% by weight), and Ma is        the molecular weight of the (E) alkaline earth metal compound,        and 2 in the expression indicates the valence of the alkaline        earth metal.)

This expression indicates that it is preferable that the adding amountof the alkali metal compound be an empirically verified specific amountwith respect to the adding amount of the phosphoric acid ester in orderto enhance the hydrolysis resistance and the metal pollutioncharacteristic. In the case where the adding amount of the alkalineearth metal compound is below this range, the improving effect is small.In the case where the adding mount is above the range, the hydrolysisresistance and the metal pollution characteristic are deteriorated.Therefore, both cases are not preferable.

The (F) epoxy compound may further be compounded. As the epoxy compound,glycidyl ester compounds, glycidyl ether compound and glycidyl esterether compounds may be cited. These may be used in a fashion of one ormore species.

Furthermore, in order to realize the exellent improving effect on thehydrolysis resistance of the PBT, an epoxy compound of less than 500 inepoxy equivalent is preferable, and furthermore an epoxy compound ofless than 400 in epoxy equivalent is particularly preferable. The epoxyequivalent herein is an epoxy compound wherein the number of grams ofthe epoxy compound that contains 1 gram equivalent of epoxy group isless than 500. The epoxy equivalent can be determined by a method inwhich an epoxy compound is dissolved in pyridine, and 0.05N hydrochloricacid is added thereto, and after being heated at 45° C., the solution isback-titrated with 0.05N caustic soda by using a mixed liquid of thymolblue and cresol red as an indicator.

Furthermore, as for the aforementioned epoxy compound, a monofunctionalglycidyl ester compound or an epoxy compound in which a glycidyl ethercompound and a monofunctional glycidyl ester compound are both employedare preferably used. Particularly, a monofunctional glycidyl estercompound is more preferable from the balance between the viscositystability and the hydrolysis resistance of the resultant composition.

Furthermore, the aforementioned glycidyl ester compound is notparticularly limited. As specific examples, benzoic acid glycidyl ester,tBu-benzoic acid glycidyl ester, P-toluic acid glycidyl ester,cyclohexane carboxylic acid glycidyl ester, pelargonic acid glycidylester, stearic acid glycidyl ester, lauric acid glycidyl ester, palmiticacid glycidyl ester, behenic acid glycidyl ester, versatic acid glycidylester, oleic acid glycidyl ester, linoleic acid glycidyl ester,linolenic acid glycidyl ester, behenol acid glycidyl ester, stearol acidglycidyl ester, terephthalic acid diglycidyl ester, isophthalic aciddiglycidyl ester, phthalic acid diglycidyl ester,naphthalenedicarboxylic acid diglycidyl ester, bibenzoic acid diglycidylester, methyl terephthalic acid diglycidyl ester, hexahydrophthalic aciddiglycidyl ester, tetrahydrophthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester,succinic acid diglycidyl ester, sebacic acid diglycidyl ester,dodecanedionic acid diglycidyl ester, octadecane dicarboxylic aciddiglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acidtetraglycidyl ester, etc. may be cited. As for these, the use of onespecies or two or more species is possible.

Furthermore, the aforementioned glycidyl ether compound is notparticularly limited. As specific examples, phenyl glycidyl ether,o-phenyl phenyl glycidyl ether, 1,4-bis(β,γ-epoxypropoxy)butane,1,6-bis(β,γ-epoxypropoxy)hexane, 1,4-bis(β,γ-epoxypropoxy)benzene,1-(β,γ-epoxypropoxy)-2-ethoxyethane,1-(β,γ-epoxypropoxy)-2-benzyloxyethane,2,2-bis-[p-(β,γ-epoxypropoxy)phenyl]propane, and diglycidyl ethersobtained by reactions of other bisphenols, such asbis-(4-hydroxyphenyl)methane, etc., with epichlorohydrin, etc., may becited. As for these, the use of one species or two or more species ispossible.

Furthermore, the compounding amount of the (F) epoxy compound ispreferably 0.05–5% by weight, and particularly preferably 0.1–4% byweight, in respect of the mechanical characteristic and hydrolysisresistance.

It is possible to compound a fiber reinforcement material in order toenhance the mechanical strength. As the fiber reinforcement material,glass fiber, aramid fiber, carbon fiber, etc., may be cited. As theaforementioend glass fiber, glass fibers which are of a chopped strandtype or a roving type for use as a reinforcement material for ordinarypolybutylene terephthalate resins and which have been treated with asizing agent that contains a silane coupling agent, such as anaminosilane compound, an epoxysilane compound, etc., and/or urethane,vinyl acetate, one or more species of epoxy compounds, such as bisphenolA diglycidyl ethers, novolak based epoxy compounds, etc., etc., arepreferably used. Furthermore, the silane coupling agent and/or thesizing agent mentioned above may be used as an emulsion liquid.

Furthermore, if a fiber reinforcement material is compounded, thecompounding amount thereof is preferably 1–45% by weight, andparticularly preferably 5–40% by weight, in view of the fluidity duringforming and the durability of forming machines and molds.

Furthermore, an inorganic filler other than the fiber reinforcementmaterial may further be compounded, which is for improving portions ofthe crystallization characteristic, arc resistance, anisotropy,mechanical strength, flame retardancy, heat deformation temperature,etc. of the composition. As the inorganic filler other than the fiberreinforcement material, inorganic fillers in a spicular form, a granularform, a powder form and a layer form may be cited though the inorganicfiller is not limited thereto. As specific examples, glass beads, milledfiber, glass flakes, potassium titanate whisker, calcium sulfatewhisker, wollastonite, silica, kaolin, talc, smectite based clayminerals (montmorillonite, hectorite), vermiculite, mica,fluoro-taeniolite, zirconium phosphate, titanium phosphate, dolomite,etc., may be cited, and may be used in a fashion of one or more species.Furthermore, on the inorganic filler other than the fiber reinforcementmaterial, a surface treatment, such as an ionization treatment, etc.,epoxy compound, a coupling agent treatment, may be performed.Furthermore, the average particle diameter of the granular-form,powder-form and layer-form inorganic fillers is preferably 0.1–20 μm,and particularly preferably 0.2–10 μm, in view of impact strength.Furthermore, the compounding amount of the inorganic filler other thanthe fiber reinforcement material is preferably an amount whose sum withthe compounding amount of the fiber reinforcement agent does not exceed1–45% by weight, in view of the fluidity during forming and thedurability of forming machines and molds.

By compounding a fluorine based compound, the melt dripping of theflame-retardant resin composition during combustion can be restrained,and the flame retardancy can be further enhanced. The fluorine basedcompound is a compound containing fluorine in the substance's molecule.Specifically, polytetrafluoroethylene, polyhexafluoropropylene,(tetrafluoroethylene/hexafluoropropylene) copolymer,(tetrafluoroethylene/perfluoroalkyl vinyl ether) copolymer,(tetrafluoroethylene/ethylene) copolymer,(hexafluoropropylene/propylene) co-polymer, polyvinylidene fluoride,(vinylidene fluoride/ethylene) copolymer, etc., may be cited. Inparticular, polytetrafluoroethylene, (tetrafluoroethylene/perfluoroalkylvinyl ether) copolymer, (tetrafluoroethylene/hexafluoropropylene)copolymer, (tetrafluoroethylene/ethylene) copolymer and polyvinylidenefluoride are preferable, and particularly polytetrafluoroethylene and(tetrafluoroethylene/ethylene) copolymer are preferable. Furthermore, ifthe fluorine based compound is compounded, the compounding amountthereof is 0.02–5% by weight, preferably 0.1–3% by weight, and morepreferably 0.2–2% by weight, in view of flame retardancy and mechanicalcharacteristic.

The flame retardancy can be further enhanced by further compounding apolycarbonate resin. As the aforementioned polycarbonate resin, aromatichomo- or co-polycarbonates obtained by reacting an aromatic dihydricphenol based compound and phosgene or carbonic acid diester may becited. The aromatic homo- or co-polycarbonate resin is a resin whoseweight-average molecular weight is in the range of 10,000–1100,000. Ifthe glass transition temperature is about 150° C. and the weight-averagemolecular weight is in the range of 10,000–1,000,000, polycarbonateresins different in weight-average molecular weight may be usedtogether. Polycarbonate resins having a weight-average molecular weightin the range of 60,000–1,100,000 are particularly preferably used. Theweight-average molecular weight is a one obtained through measurement interms of polystyrene by a gel permeation chromatography usingtetrahydrofuran as a solvent. If the weight-average molecular weight is10,000 or less, the excellent mechanical characteristic of the presentinvention is impaired, and therefore such weight-average molecularweight is not preferable. If the weight-average molecular weight is110,000 or greater, the fluidity during forming is impaired, andtherefore such weight-average molecular weight is not preferable.

Furthermore, polycarbonate resins whose melt viscosity index (melt flowindex) measured by a melt indexer according to ASTM D1238 in theconditions of a temperature of 300° C. and a load of 1.2 kg is in therange of 1–100 g/10 min., and particularly 1–15 g/10 min. are preferablyused in view of mechanical characteristic.

As the aromatic dihydric phenol based compound,2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, bis(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane,2,2-bis(4-hydroxy-3,5-diphenyl)butane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethyl phenyl)propane,1,1-bis(4-hydroxyphenyl)cyclohexane,1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, etc. may be used. These may beused singly or as a mixture. However, if an amount of polycarbonateresin exceeding 5% by weight is compounded, the hydrolyzability maysometimes considerably deteriorate, and therefore, attention is needed.A preferable compounding amount of polycarbonate resin is less than0.1–5% by weight, and preferably 0.5–3% by weight, from theaforementioned hydrolysis resistance and flame retardancy. Furthermore,a polycarbonate resin oligomer may be compounded if the amount thereofis in such a range that the characteristics of the composition will notbe impaired.

By compounding a small amount of an acidic phosphoric acid ester whenthe aforementioned polycarbonate resin is compounded, it is useful as antransesterification preventing agent for the (A) component and thepolycarbonate resin, and particularly prevents decreases in the heatdeformation temperature, etc. The aforementioned acidic phosphoric acidester is an alkyl acid phosphate compound of a partial ester between analcohol or the like and a phosphoric acid, And a low-molecular weightone is colorless liquid, and a high-molecular weight one is in a whitewax-form or flake-form solid. Specific examples of the aforementionedacidic phosphoric acid ester, although it is not limited thereto, may bemonomethyl acid phosphate, monoethyl acid phosphate, monoisopropyl acidphosphate, monobutyl acid phosphate, monolauryl acid phosphate,monostearyl acid phosphate, monododecyl acid phosphate, monobehenyl acidphosphate, dimethyl acid phosphate, diethyl acid phosphate, diisopropylacid phosphate, dibutyl acid phosphate, lauryl acid phosphate, distearylacid phosphate, didodecyl acid phosphate, dibehenyl acid phosphate,trimethyl acid phosphate, triethyl acid phosphate, and mixtures of theaforementioned mono's and di's, mixtures of the aforementioned mono's,di's and tris', mixtures of one or more species of the aforementionedcompounds. As acidic phosphoric acid esters preferably used, long chainalkyl acid phosphate compounds, such as mixtures of mono- and di-stearylacid phosphates, etc., may be cited, and such a compound is commerciallysold in the name of “Adeka Stab” AX-71 by Asahi Denka Co., and is aflake-form solid having a melting point.

The compounding amount of the aforementioned acidic phosphoric acidester is preferably 0.01–0.5% by weight, and particularly preferably0.02–0.3% by weight, in view of heat deformation temperature andmechanical characteristic.

A flame retarding assistant that assists in flame retardancy, such as asilicone compound, a phenol resin, a phosphonitrile compound,polyammonium phosphate, polymelamine phosphate, etc., may further becompounded. Such assistants may be used in a fashion of one or morespecies. If the aforementioned flame retarding assistant is compounded,the compounding amount thereof is preferably 1–10% by weight, andparticularly preferably 2–7.5% by weight, in view of flame retardancyand mechanical properties.

As the aforementioned silicone compound, silicone resin, silicone oiland silicone powder may be cited.

As the aforementioned silicone resin, polyorganosilanes in whichsiloxane and a group selected from saturated or unsaturated monovalenthydrocarbon radical, hydrogen atom, hydroxyl group, alkoxyl group, arylgroup, vinyl or allyl group, are chemically bonded, may be cited. Oneshaving a viscosity of about 200–300000000 centipoises at roomtemperature are preferable; however, as long as one is a silicone resinas mentioned above, it is not restricted by that. The productconfiguration may be an oil form, a powder form, or a gum form.Introduction of epoxy group, methacryl group and amino group as afunctional group is permissible. A mixture of two or more species ofsilicone resins is also permissible.

As the silicone oil, polyorganosilanes in which siloxane and a groupselected from saturated or unsaturated monovalent hydrocarbon radical,hydrogen atom, hydroxyl group, alkoxyl group, aryl group, vinyl or allylgroup, are chemically bonded, may be cited. Ones having a viscosity ofabout 0.65–100,000 centistokes at room temperature are preferable;however, as long as one is a silicone oil resin as mentioned above, itis not restricted by that. The product configuration may be an oil form,a powder form, or a gum form. Introduction of epoxy group, methacrylgroup and amino group as a functional group is permissible. A mixture oftwo or more species of silicone oils or silicone resins is alsopermissible.

As the silicone powder, ones in which an inorganic filler is compoundedwith the aforementioned silicone resin and/or silicone oil may be cited.As the inorganic filler, silica, etc. may be preferably used.

The aforementioned phenol resin is an arbitrary one if it is amacromolecule having a plurality of phenolic hydroxyl groups. Forexample, novolac type, resole type and heat-reactive type resins, orresins modified therefrom may be cited. These may be an uncured resin inwhich a curing agent is not added, a semi-cured resin, or a cured resin.In particular, curing agent-unadded and non-heat reactive novolac typephenol resins or melamine-modified novolac type phenol resins arepreferable in view of flame retardancy, mechanical property and economy.

The configuration thereof is not preferably restricted, but any one of amilled product, a granular form, a flake form, a powder form, a spicularform, a liquid form, etc., may be employed. In accordance with need, onespecies or two or more species thereof may be employed. The phenol basedresin is not particularly limited, and commercially sold ones, etc. areused. For example, in the case of a novolac type phenol resin, a phenolor the like and an aldehyde or the like are placed in a reaction chamberat such a ratio that the molar ratio therebetween is 1:0.7–1:0.9. Aftera catalyst, such as oxalic acid, hydrochloric acid, sulfuric acid,toluene, sulfonic acid, etc., is added, heating is performed to conducta reflux reaction for a predetermined time. In order to remove thegenerated water, vacuum dehydration or still-standing dehydration isperformed. Furthermore, remaining water and unreacted phenol or the likeare removed. By this method, a novolac type phenol resin can beobtained. These resins or copolycondensed phenol resins obtained byusing a plurality of material components may be used singly, or two ormore species thereof may be used.

In the case of resole type phenol resin, the resin can be obtained byplacing a phenol or the like and an aldehyde or the like in a reactionchamber at such a ratio that the molar ratio therebetween is 1:1–1:2,and adding a catalyst, such as a sodium hydroxide, an ammonia water orother basic substance, etc., and then conducting the reaction andtreatment similar to those of the novolac type phenol resin.

As the phenol or the like, phenol, o-cresol, m-cresol, p-cresol, thymol,p-tert-butyl phenol, tert-butyl catechol, catechol, isoeugenol,o-methoxy phenol, 4,4′-dihydroxyphenyl-2,2-propane, isoamyl salicylate,benzyl salicylate, methyl salicylate, 2,6-di-tert-butyl-p-cresol, etc.may be cited. As for these phenols and the like, one species or two ormore species may be used. On the other hand, the aldehyde or the like,formaldehyde, paraformaldehyde, polyoxymethylene, trioxane, etc., may becited. As for these aldehydes and the like, one species or two or morespecies may be used in accordance with need.

The molecular weight of the phenol based resin is not particularlylimited, but is preferably 200–2,000 in number-average molecular weight.In particular, ones in the range of 400–1,500 are preferable as they areexcellent in mechanical property, fluidity and economy. Incidentally,the molecular weight of phenol based resin can be measured through a gelpermeation chromatography method by using a tetrahydrafuran solution anda polystyrene standard sample.

As for the aforementioned phosphonitrile compound, phosphonitrilecompounds having a phosphonitrile linear polymer and/or cyclic polymeras a main component may be cited, and may well be of a straight chainform or a cyclic form, or a mixture thereof. The aforementionedphosphonitrile linear polymer and/or cyclic polymer may be synthesizedby a known method described in “Synthesis and Application of PhosphazeneCompounds” authored by Kajiwara, etc. For example, it can be synthesizedby reacting phosphorous pentachloride or phosphorous trichloride as aphosphorous source, and ammonium chloride or an ammonia gas as anitrogen source by a known method (purifying a cyclic substance is alsopermissible), and substituting the obtained matter with alcohol, phenol,and an amine or the like.

As the aforementioned polyammonium phosphate, polyammonium phosphate,melamine-modified polyammonium phosphate, carbamoyl polyammoniumphosphate, etc., may be cited. These may be coated with a thermosettingresin that exhibits a thermosetting characteristic, such as phenolresin, urethane resin, melamine resin, urea resin, epoxy resin, urearesin, etc., and may be used in a one-species fashion, and may also beused in a two-or-more species fashion.

As the aforementioned polymelamine phosphate, polymelamine phosphates ofmelamine phosphate, melamine pyrophosphate, etc., may be cited. Thesemay be used in a one-species fashion, and may also be used in atwo-or-more species fashion.

An ethylene (co)polymer may further be compounded for the purpose ofimproving the toughness of the composition, such as the impact strength,etc. As the ethylene (co)polymer, ethylene polymers, such as highdensity polyethylene, low density polyethylene, very low densitypolyethylene, etc., and/or ethylene copolymers. The foregoing ethylenecopolymer is obtained by copolymerizing ethylene and a monomercopolymerizable therewith. As the copolymerizable monomer, propylene,butene-1, vinyl acetate, isoprene, butadiene, or monocarboxylic acidsand the like, such as acrylic acid, methacrylic acid, etc., or esteracids and the like thereof, dicarboxylic acids and the like, such asmaleic acid, fumaric acid, itaconic acid, etc., etc. may be cited. Theethylene copolymer can be produced by an ordinarily known method. Asspecific examples of the ethylene copolymer, ethylene/propylene,ethylene/butene 1, ethylene/vinyl acetate, ethylene/ethyl acrylate,ethylene/methyl acrylate, ethylene/ethyl methacrylate acrylate, etc. maybe cited. Furthermore, copolymers in which an acid anhydride or glycidylmethacrylate is graft- or co-polymerized with the aforementionedethylene (co)polymer may preferably be used. These are used in a fashionof one species or two or more species, and may be used as a mixture withone or more species of the aforementioned ethylene (co)polymers.Furthermore, among the ethylene (co)polymers, a copolymer in which anacid anhydride or a glycidyl methacrylate is graft- or polymerized withpolyethylene is preferably used since its compatibility with the (A)component is good. Furthermore, if the ethylene (co)polymer iscompounded, the compounding amount thereof is preferably 1–10% byweight, and particularly preferably 2–7.5% by weight, in view of theflame retardancy and the impact strength of the resultant composition.

Phenoxy resin, an oxazoline compound, a carbodiimide compound, etc.,which are hydrolysis resistance-improving materials, may be compounded.Particularly, phenoxy resin is preferably used. Furthermore, if theaforementioned hydrolysis resistance-improving material is compounded,the compounding amount thereof is preferably 0.1–7.5% by weight, andparticularly preferably 0.2–5% by weight, in view of the hydrolysisresistance and the flame retardancy of the resultant composition.

Furthermore, as the aforementioned phenoxy resin, phenoxy resinsobtained by reacting an aromatic dihydric phenol based compound andepichlorohydrin at various compounding proportions may be cited. Themolecular weight of the phenoxy resin is not particularly limited, butis preferably in the range of 1,000–100,000 in viscosity-averagemolecular weight. Here, as examples of the aromatic dihydric phenolbased compound, 2,2-bis(4-hydroxyphenyl)propane,2,2-bis(4-hydroxy-3,5-dimethyl phenyl)propane,bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxy-3,5diethyl phenyl)propane,1,1-bis(4-hydroxyphenyl)cyclohexane,1-phenyl-1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxyphenyl)methane, etc., may be used. These may be usedsingly or as a mixture. The configuration thereof is not particularlyrestricted, but any one of a milled product, a granular form, a flakeform, a powder form, a spicular form, a liquid form, etc., may beemployed. As for these phenoxy resins, one species or two or morespecies of may be used in accordance with need.

A hindered phenol antioxidant and/or a phosphite antioxidant may furtherbe compounded as a stabilizing agent for providing very good anti-heataging characteristic even if the composition of the is exposed to hightemperature for a long time may be compounded. If a hindered phenolantioxidant and/or a phosphite antioxidant is compounded, thecompounding amount thereof is preferably 0.1–2% by weight, andparticularly preferably 0.2–1% by weight, in view of anti-heat agingcharacteristic and flame retardancy.

Furthermore, as specific examples of the aforementioned hindered phenolantioxidant, triethyleneglycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate],1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester,1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, bisor tris(3-t-butyl-6-methyl-4-hydroxyphenyl)propane,N,N′-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamaide),N,N′-trimethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamaide), etc. maybe cited.

Furthermore, as examples of the aforementioned phosphite anti-oxidant,tris(2,4-di-t-butyl phenyl)phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, trisnonylphenyl phosphite, alkyl allyl basedphosphite, trialkyl phosphite, triallyl phosphite, pentaerythritol basedphosphite compounds, etc., may be cited.

It is possible to improve the fluidity and the mold releasability duringforming by adding one or more species of lubricants. As the lubricant,metallic soaps, such as calcium stearate, barium stearate, etc., fattyacid esters, salts of fatty acid esters (including partiallysalt-converted ones as well), fatty amides, such asethylenebisstearoamide, etc., fatty amides made of polycondensates madeof ethylene diamine, stearic acid and sebacic acid, or polycondensatesof phenylene diamine, stearic acid and sebacic acid, polyalkylene wax,acid anhydride-modified polyalkylene wax, and mixtures of aforementionedlubricants with fluorine based resins or fluorine based compounds may becited. However, the aforementioned lubricant is not limited thereto. Ifa lubricant is compounded, the compounding amount thereof is preferably0.05–2% by weight, and more preferably 0.1–1% by weight.

It is also possible to tone resins to various colors and improve theweather (light) resistance and the electrical conductivity bycompounding one of more species of carbon black, titanium oxide andvarious color pigments and dyes. The compounding amount thereof ispreferably 0.1–3% by weight, and more preferably 0.1–2% by weight, inview of the mechanical characteristic of the resultant composition.

As for the aforementioned carbon black, there is no limitation, butchannel black, furnace black, acetylene black, anthracene black, lampblack, pine black, graphite, etc. may be cited. Carbon blacks having anaverage particle diameter of 500 nm less and a dibutyl phthalate oilabsorption amount of 50–400 cm³/100 g may be preferably used. Treatmentwith aluminum oxide, silicon oxide, zinc oxide, zirconium oxide, polyol,a silane coupling agent, etc. as a treating agent is also permissible.

Furthermore, as for the aforementioned titanium oxide, titanium oxideshaving a crystal form of a rutile type, an anatase type, etc., andhaving an average particle diameter of 5 μm or less are preferably used,and treatment with aluminum oxide, silicon oxide, zinc oxide, zirconiumoxide, polyol, a silane coupling agent, etc. as a treating agent is alsopermissible. Furthermore, the carbon black, the titanium oxide and thevarious color pigments and dyes mentioned above may be used as a mixedmaterial melt-blended or simply blended with various thermoplasticresins, in order to enhance the dispersibility with respect to theflame-retardant resin composition of the present invention and enhancethe handling characteristic during production. Particularly, as theaforementioned thermoplastic resins, polyalkylene terephthalate ispreferably used.

It is also possible to add one or more species of known non-halogenatedflame retardants other than the present invention, so that reduction ofthe combustion time during combustion or reduction of gas generatedduring combustion can be expected. As for the known non-halogenatedflame retardants, there is no limitation, but, for example, aluminumhydroxide, hydrotalcite, boric acid, calcium borate, calcium boratehydrate, zinc borate, zinc borate hydrate, zinc hydroxide, zinchydroxide hydrate, zinc tin hydroxide, zinc tin hydroxide hydrate, redphosphorus, thermally expanded graphite, dawsonite, etc. may be cited.Mixture or surface coating with a thermosetting resin, such as athermosetting melamine resin, a thermosetting phenol resin, athermosetting epoxy resin, etc., is also permissible. Furthermore,mixture or surface coating with a coupling agent, an epoxy compound, ora fat-and-oil or the like, such as stearic acid, etc., etc., is alsopermissible.

Still further, a material in which one or more species of knownadditives, such as an sulfur type antioxidant, an ultraviolet absorber,a plasticizer, an antistatic agent, etc., are compounded may be used insuch a range that the purposes of the present invention are notimpaired, in the flame-retardant polybutylene terephthalate resincomposition and formed article of the present invention.

Although addition of a polyphenylene ether resin or a polyphenylenesulfide resin is preferable in order to further improve the flameretardancy, the addition thereof may sometimes deteriorate the trackingresistance, hydrolysis resistance, metal pollution characteristic, andit is preferable that those resins not be compounded. If a resinmentioned above is compounded, it is preferable that the amount thereofnot exceed 5% by weight.

The flame-retardant polybutylene terephthalate resin composition andformed article are produced by ordinarily known methods. For example,(A) a polybutylene terephthalate resin or a mixture of a polybutyleneterephthalate resin and a polyethylene terephthalate resin, (B) a vinylbased resin, (C) a phosphoric acid ester, (D) a salt of a triazine basedcompound and cyanuric acid or isocyanuric acid, (E) an alkaline earthmetal compound, and, in accordance with need, (F) an epoxy compound, afiber reinforcement material, such as glass fiber, etc., andfurthermore, in accordance with need, an inorganic filler other than thefiber reinforcement material, a fluorine based compound, a polycarbonateresin, various flame retarding assistants, an ethylene (co)polymer, ahydrolysis resistance improving material, a hindered phenol antioxidantand/or a phosphite antioxidant, and still further, in accordance withneed, other necessary additives, coloring agents, such as pigments,dyes, etc., are pre-mixed or not pre-mixed, and are then supplied to anextruder, etc., and are thoroughly melted and kneaded, whereby aflame-retardant polybutyrerene terephthalate resin composition isprepared.

As an example of the aforementioned premixing, the mixing through theuse of a mechanical mixing device, such as a tumbler, a ribbon mixer, aHenschel mixer, etc., may be cited, although the dry blending alone canstill deliver the desired effects. Furthermore, as for the fiberreinforcement material, a method in which a side feeder is disposed atan intermediate point between the breech-loading portion and a ventportion of a multi-screw extruder, such as a twin-screw extruder, etc.,and the material is loaded through the side feeder, is also permissible.Furthermore, in the case of a liquid additive, a method in which aliquid loading nozzle is disposed at an intermediate point between thebreech-loading portion and a vent portion of a multi-screw extruder,such as a twin-screw extruder, etc., and the additive is loadedtherethrough by using a plunger pump, or a method in which the additiveis supplied through the breech-loading portion, etc. with a meteringpump, etc. is also permissible.

Furthermore, in production of the flame-retardant polybutyleneterephthalate resin composition, it is possible to use a single-screwextruder, a twin-screw extruder or a three-screw extruder equipped with,for example, “Unimelt” or “Dulmage” type screws, or a kneader typekneading machine, etc. although this is not restrictive.

The thus-obtained flame-retardant polybutylene terephthalate resincomposition can be formed by ordinarily known methods. For example, byinjection molding, extrusion molding, compression molding, sheetforming, film forming, etc., the resin composition can be made intoformed articles of any configuration. In particular, injection moldingis preferred, and a formed article obtained by an injection moldingmethod based on insert molding in which a portion of a metalliccomponent part is directly integrated with a formed article is alsopermissible.

EXAMPLES

The effects of the composition will be described further in detail withreference to examples. Herein, % and part(s) all represent % by weightand parts by weight, and “/” in reference examples meanscopolymerization. Measurement methods for individual characteristics areas follows.

Reference Example 1 (A) Polybutylene Terephthalate Resin (Hereinafter,Simply Referred to as PBT)

<A-1> Toray PBT-1100S (produced by Toray Co.): A PBT of 0.85 inintrinsic viscosity (25° C., an ortho-chlorophenol solvent) was used.

Reference Example 2 (A) Polyethylene Terephthalate Resin (Hereinafter,Simply Referred to as PET)

<A-2> Mitsui PETJ005 (produced by Mitsui PET Resin Co.): A PET of 0.65in intrinsic viscosity (25° C., a mixed solvent ofphenol/tetrachloroethane at 1:1) was used.

Reference Example 3 (B) Vinyl Based Resin

<B-1> An acrylonitrile/styrene copolymer (hereinafter, simply referredto as AS) of acrylonitrile/styrene copolymer (13/87% by weight) wasused. Incidentally, the limiting viscosity thereof measured at 30° C. ina methyl ethyl ketone solvent is 0.42 dl/g.

<B-2> An As of acrylonitrile/styrene copolymer (26/74% by weight) wasused. Incidentally, the limiting viscosity thereof measured at 30° C. ina methyl ethyl ketone solvent is 0.45 dl/g.

<B-3> An AS of acrylonitrile/styrene copolymer (45/55% by weight) wasused. Incidentally, the limiting viscosity thereof measured at 30° C. ina methyl ethyl ketone solvent is 0.48 dl/g.

<B-4> An epoxy-modified AS of acrylonitrile/styrene/glycidylmethacrylate copolymer (25.5/74/0.5% by weight) was used. Incidentally,the limiting viscosity thereof measured at 30° C. in a methyl ethylketone solvent is 0.53 dl/g.

<B-5> An AS of acrylonitrile/styrene copolymer (7/93% by weight) wasused. Incidentally, the limiting viscosity thereof measured at 30° C. ina methyl ethyl ketone solvent is 0.40 dl/g.

<B-6> An AS of acrylonitrile/styrene copolymer (55/45% by weight) wasused. Incidentally, the limiting viscosity thereof measured at 30° C. ina methyl ethyl ketone solvent is 0.49 dl/g.

<B-7> A polystyrene resin (hereinafter, simply referred to as PS)(“Estyrene” G13 produced by Shinnittetsu Kagaku Kogyo Co.) was used.

<B-8> A polymethyl methacrylate resin (hereinafter, simply referred toas PMMA) (“Acrypet” MF produced by Mitsubishi Rayon Co.) was used.

<B-9> An acrylonitrile/butadiene/styrene copolymer (hereinafter, simplyreferred to as ABS), (“Toyolac” type 100 produced by Toray Co.) wasused.

<B-10> Core: A silicone/acrylic polymer was used. Shell: A methylmethacrylate polymer (“Metablen” S2001 produced by Mitsubishi Rayon Co.)was used.

<B-1> Core: A silicone/acrylic polymer was used. Shell:acrylonitrile/styrene polymer (“Metablen” SX006 produced by MitsubishiRayon Co.) was used.

<B-12> Core: A silicone/acrylic polymer was used. Shell: A methylmethacrylate/glycidyl methacrylate polymer (“Metablen” KS0205 producedby Mitsubishi Rayon Co.) was used.

Reference Example 4 (C) Phosphoric Acid Ester

<C-1> An aromatic phosphoric acid ester “PX-200” (produced by DaihachiKagaku Co.) of the following expression (6) was used.

<C-2> An aromatic phosphoric acid ester “CR741” (produced by DaihachiKagaku Co.) of the following expression (7) was used.

Reference Example 5 (D) Salt of a Triazine Based Compound and CyanuricAcid or Isocyanuric Acid

<D-1> A melamine cyanurate “MCA” (produced by Mitsubishi Kagaku Co.) wasused (hereinafter, simply referred to as MC salt).

Reference Example 6 (E) Alkaline Earth Metal Compound

<E-1> Magnesium hydroxide “Kisuma 6E” (produced by Kyowa Kagaku KogyoCo.)

<E-2> Calcium carbonate “KSS1000” (produced by Dowa Calfine Co.)

Reference Example 7 (F) Epoxy Compound

<F-1> Versatic acid glycidyl ester “Cardura E10” (produced by JapanEpoxy Resin Co.) (hereinafter, simply referred to as monofunctionalglycidyl ester)

<F-2> A mixture of 30% by weight of versatic acid glycidyl ester“Cardura E10” (produced by Japan Epoxy Resin Co.) and 70% by weight ofbisphenol A diglycidyl ether “Epikote 828” (produced by Japan EpoxyResin Co.). (hereinafter, simply referred to as a mixture ofmonofunctional diglycidyl ester and didiglycidyl ether)

Reference Example 8 Fiber Reinforcement Material

<G-1> A chopped strand-form glass fiber “CS3J948” (produced by NittoBoseki Co.) having a fiber diameter of 10 μm was used (hereinafter,simply referred to as GF).

Reference Example 9 Fluorine Based Compound

<H-1> A polytetrafluoroethylene “Teflon® 6-J” (produced by Mitsui-DuPontFluorochemicals Co.) was used (hereinafter, simply referred to asTeflon).

Reference Example 10 Silicone Compound

<I-1> A silicone powder “DC4-7105” (produced by Toray Dow CorningSilicone Co.) was used.

Reference Example 11 Phenol Resin

<I-2> A novolac type phenol resin “Sumilite Resin” PR53195(produced bySumitomo Durez Co.) was used.

Reference Example 12 Phosphonitrile Compound

<I-3> A hexachlorocyclotriphosphazene (cyclic trimer) and phenol werereacted in the presence of triethyl amine in THF. The resultant reactionliquid was evaporated and dried, and was washed with water to removesalt. Yield: 95%. The thus-obtained phosphonitrile cyclic polymer waspurified by recrystallization from acetone, and then was used. There wasno change in the number-average polymerization degree n, but n=3.

Reference Example 13 Ethylene Copolymer

<J-1> An ethylene ethyl acrylate copolymer “A-709” (produced byMitsui-DuPont Polychemicals Co.) was used.

Reference Example 14 Hydrolysis Resistance-Improving Material

<K-1> A phenoxy resin “Phenotohto” YP-50 (produced by Tohto Kasei KogyoCo.) was used.

Reference Example 15 Hindered Phenol Antioxidant and/or PhosphiteAntioxidant

<L-1> A hindered phenol antioxidant “IR-1010” (produced by NipponCiba-Geigy Co.) ofpentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate].

<L-2> A phosphite antioxidant “Mark PEP-36” (produced by Asahi DenkaCo.) of pentaerythritol based phosphite compound.

Reference Example 16 Polycarbonate Resin “Iupilon” S-3000 (Produced byMitsubishi Engineering-Plastics Co.) (Hereinafter, Simply Referred to asPC). Reference Example 17 Polyphenylene Ether Resin “YPX-100L” (Producedby Mitsubishi Engineering-Plastics Co.) (Hereinafter, Simply Referred toas PPE). Reference Example 18 Polyphenylene Sulfide “Torelina” M2588(Produced by Toray Co.) (Hereinafter, Simply Referred to as PPS)Examples 1–32, Comparative Examples 1–15

Using a co-rotating vent-equipped twin-screw extruder having a screwdiameter of 30 mm and an L/D of 35 (TEX-30α produced by Nihon Seikosho),(A) PBT, PET, (B) a vinyl based resin, (C) a phosphoric acid ester, and(D) MC salt, and <E> an alkaline earth metal compound, as well as otheradditives <F>, <G>, <H>, <I>, <J>, <K>, <L>, etc. were mixed as incompounding compositions shown in Table 1–Table 5, and were loadedthrough a breech-loading portion; In the examples in which the GF of <G>was compounded, a side feeder was disposed at an intermediate pointbetween the breech-loading portion and the vent portion, and the loadingamounts of compounded materials shown Table 1 were loaded through thebreech-loading portion in the same manner as described above, exceptthat a side feeder was disposed at an intermediate point between thebreech-loading portion and the vent portion. Melt mixture was performedin extrusion conditions of a kneading temperature of 270° C. and a crewrotation of 150 rpm, to eject the material in a strand form, which waspassed through a cooling bath, and then pelletized by a strand cutter.

After the obtained pellets were dried, an injection molding machine wassubsequently used to form various test pieces, and properties thereofwere measured in the following conditions. Results are shown in Table1–Table 5.

(1) Flame Retardancy

Using an IS55 EPN injection molding machine produced by Toshiba Kikai,injection molding of test pieces for flame retardancy evaluation wasperformed in the conditions of a molding temperature of 260° C. and amold temperature of 70° C. In accordance with the evaluation criteriondefined in the UL94 vertical test, the flame retardancy thereof wasevaluated. The flame retardancy decreases in the order of V-0>V-1>V-2,and the ranking was performed. As for the thickness of the test pieces,a thickness of 1/32 inch (about 0.79 mm, which is hereinafter simplyreferred to as about 0.8 mm), and a thickness of 1/64 inch (about 0.40mm, which is hereinafter simply referred to as about 0.4 mm) wereemployed. Less thicknesses face severer evaluations in flame retardancy.Materials that were inferior in flame retardancy and did not reach theaforementioned V-2 and did not fall into any one of the aforementionedflame retardancy ranks were evaluated as nonstandard.

(2) Tensile Strength

Using an IS55 EPN injection molding machine produced by Toshiba Kikai,injection molding of ASTM #1 dumbbells of 3 mm in thickness wasperformed in the conditions of a molding temperature of 260° C. and amold temperature of 70° C. Tensile strengths of the dumbbells weremeasured according to ASTM D638.

(3) Hydrolysis Resistance

The aforementioned ASTM #1 dumbbell pieces of 3 mm in thickness weresubjected to a wet heat treatment for 100 hours in a pressure cookertester TPC-411 produced by Tabai Co. in the conditions of a temperatureof 121° C. and a humidity of 100% RH. After that, tensile strengthsthereof were measured as described above. Measured values were dividedby the tensile strength of an untreated piece, and values thus obtainedare presented as percentages, that is, tensile strength retention rates(%).

(4) Tracking Resistance

Using, as specimens, square plates of 80 mm×80 mm×3 mm in thicknessinjection-molded in the conditions of a molding temperature of 260° C.and a mold temperature of 70° C. through the use of an IS55 EPNinjection molding machine produced by Toshiba Kikai, 0.1% ammoniumchloride aqueous solution as an electrolyte solution was dropped atevery 30±5 seconds according to the test method presented in the IECPublication 112 standard. The numbers of drops of the electrolytesolution and the applied voltages before destruction was reached wereplotted. An applied voltage causing destruction with 50 drops was readfrom the graph, and the read numerical value was defined as a relativetracking index (V).

(5) Metal Pollution Characteristic

About 10 g of pellets was placed in a 100-cc Erlenmeyer flask equippedwith a stopper, a silver plate of about 5×10 mm×0.5 mm in thickness washung in an upper portion of the flask with a cotton thread and thestopper was set. Then, a seal tape was wound around a stopper portion.After that, the flask was placed in a hot air dryer “HighTempOven”PVH210 produced by Tabai Co. whose temperature was controlled at 120°C., and was heat-treated for 100 hours.

Analysis of P atoms on a surface of the silver plate following thetreatment was performed with an SEM (reflection type electronicmicroscope “S-2000A type” produced by Hitachi) and an XMA (energydispersive type X-ray microanalyzer produced by Horiba Seisakusho).Herein, detection of P atoms by the SEM-XMA means the presence of aphosphorus compound on the sliver plate surface. In the case of no suchdetection, only a peak of sliver atom is detected.

0: P atoms not detected.

1: A P atom peak having a height equal to or less than 1/10 of theheight of the silver atom peak is detected.

2: A P atom peak having a height equal to or less than 2/10 of theheight of the silver atom peak is detected.

3: A P atom peak having a height equal to or less than 3/10 of theheight of the silver atom peak is detected.

5: A P atom peak having a height equal to or less than 5/10 of theheight of the silver atom peak is detected.

10: A P atom peak greater than the height of the silver atom peak isdetected.

(6) Izod Impact

Using an IS55 EPN injection molding machine produced by Toshiba Kikai,injection-molded articles of Izod impact test pieces of 3 mm inthickness were obtained in the conditions of a molding temperature of260° C. and a mold temperature of 70° C.

According to ASTM D256, Izod V notch impact strength was measured.

(7) Heat Resistance

Using an IS55 EPN injection molding machine produced by Toshiba Kikai,injection molding of ASTM #1 dumbbells of 3 mm in thickness wasperformed in the conditions of a molding temperature of 260° C. and amold temperature of 70° C. After the dumbbells were placed for 200 hoursin a hot air dryer “HighTempOven” PVH210 produced by Tabai Co. whosetemperature was controlled at 175° C., tensile strengths thereof weremeasured. Measured values were divided by the tensile strength of anuntreated piece, and values thus obtained are presented as percentages,that is, tensile strength retention rates (%).

TABLE 1 Com- pound- ing Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam-Exam- Exam- Exam- Exam- Exam- Composition amount ple 1 ple 2 ple 3 ple 4ple 5 ple 6 ple 7 ple 8 ple 9 ple 10 ple 11 ple 12 ple 13 <A-1> PBT % 2727 27 27 27 27 27 27 27 27 27 27 27 <B-1> AS ″ 8 — — — — — — — — — — — —<B-2> AS ″ — 8 — — — — — — — — — — 8 <B-3> AS ″ — — 8 — — — — — — — — —— <B-4> Epoxy- ″ — — — 8 — — — — — — — — — modified AS <B-5> AS ″ — — —— 8 — — — — — — — — <B-6> AS ″ — — — — — 8 — — — — — — — <B-7> PS ″ — —— — — — 8 — — — — — — <B-8> PMMA ″ — — — — — — — 8 — — — — — <B-9> ABS ″— — — — — — — — 8 — — — — <B-10> ″ — — — — — — — — — 8 — — — Multilayerstructure <B-11> ″ — — — — — — — — — — 8 — — Multilayer structure <B-12>″ — — — — — — — — — — — 8 — Multilayer structure <C-1> ″ 12 12 12 12 1212 12 12 12 12 12 12 — Phosphoric acid ester <C-2> ″ — — — — — — — — — —— — 12 Phosphoric acid ester <D-1> ″ 18 18 18 18 18 18 18 18 18 18 18 1818 MC salt <E-1> ″ — — — — — — — — — — — — 0.5 Magnesium hydroxide <E-2>″ 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 — Calcium carbonate<G-1> GF ″ 34.5 34.5 34.5 34.5 34.5 34.5 34.5 34.5 34.5 34.5 34.5 34.534.5 Property Unit Flame Rank V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0V-0 V-0 V-0 retardancy (about 0.8 mm thick) Tensile MPa 129 131 130 135124 112 116 114 112 112 123 118 128 strength Hydrolysis % 51 58 61 63 5348 43 41 40 40 51 44 55 resistance (tensile strength retention rate)Tracking V 650 650 650 650 625 625 550 650 550 550 600 600 600resistance Metal Rank 0 0 0 0 1 1 2 2 2 2 1 2 0 pollution character-istic

TABLE 2 Compara- Compara- Compara- Compara- Compara- Compara- Com- tivetive tive tive tive tive pounding example example example Exampleexample Example example Example example Composition amount 1 2 3 14 4 155 16 6 <A-1> PBT % 35 27 35 20 13 27 27 27 27 <B-2> AS ″ — 8 — 15 22 8 88 8 <C-1> Phosphoric ″ 12 12 12 12 12 17 22 5 — acid ester <D-1> MC salt″ 18 18 18 18 18 13 8 25 33 <E-2> Calcium ″ — — 0.5 0.5 0.5 0.5 0.5 0.50.5 carbonate <G-1> GF ″ 35 34.5 34.5 34.5 34.5 34.5 34.5 34.5 31.5Circumstances — — — — — — — — Formed during article not injectionobtained molding Property Unit Flame retardancy Rank V-0 V-0 V-0 V-1Non- V-0 V-0 V-0 — (about 0.8 standard mm thick) Tensile strength MPa121 125 122 133 124 118 103 108 — Hydrolysis resistance % 7 24 22 54 3045 11 52 — (tensile strength retention rate) Tracking V 375 625 375 650550 600 650 650 — resistance Metal pollution Rank 10 1 5 0 0 0 5 0 —characteristic

TABLE 3 Compara- Compara- Compara- Compara- Compara- Com- tive tive tivetive tive pounding Example Example Example Example example exampleexample example example Composition amount 17 18 19 20 7 8 9 10 11 <A-1>PBT % 27 27 27 27 27 27 27 27 27 <B-2> AS ″ 8 8 8 8 8 8 — — — <C-1> ″ 1212 10 10 12 12 12 12 12 Phosphoric acid ester <D-1> MC salt ″ 18 18 1813 18 18 18 18 18 <E-2> Calcium ″ 3 4 2 2.9 6 10 3 3 3 carbonate <G-1>GF ″ 32 31 35 34.5 29 25 32 32 32 PC ″ — — — — — — 8 — — PPE ″ — — — — —— — 8 — PPS ″ — — — — — — — — 8 Compounding Within the Outside theWithin the Outside the Outside the Outside the — — — ratio between rangeof range of range of range of range of range of phosphoric expressionexpression expression expression expression expression acid ester (5)(5) (5) (5) (5) (5) and alkaline earth metal Property Unit Flame RankV-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 retardancy (about 0.8 mm thick)Tensile MPa 124 116 104 118 116 104 118 113 108 strength Hydrolysis % 4833 47 34 21 8 14 25 21 resistance (tensile strength retention rate)Tracking V 650 575 650 600 575 650 450 375 375 resistance Metalpollution Rank 0 0 0 0 1 3 3 3 3 characteristic

TABLE 4 Compara- Compara- Compara- Compara- Com- tive tive tive tivepounding Example Example example example Example Example example Exampleexample Composition amount 21 22 12 13 23 24 14 25 15 <A-1> PBT % 27 2735 27 21 6 — 59 74 <A-2> PET ″ — — — — 6 21 27 — — <B-2> AS ″ 8 8 — 8 88 8 5 8 <C-2> ″ 12 12 12 12 12 12 12 13 7 Phosphoric acid ester <D-1> MCsalt ″ 18 18 18 18 18 18 18 22 10 <E-2> Calcium ″ 0.5 0.5 — — 0.5 0.50.5 0.5 0.5 carbonate <F-1> ″ 0.5 — 0.5 0.5 — — — — — Monofunctionalglycidyl ester <F-2> Mixture ″ — 0.5 — — — — — — — of monofunctional — —glycidyl ester and diglycidyl ether <G-1> GF ″ 34 34 34.5 34.5 34.5 34.534.5 <F-1> Teflon ″ — — — — — — — 0.5 0.5 Circumstances — — — — — —Formed — — during injection article not molding obtained Property UnitFlame retardancy Rank V-0 V-0 V-0 V-0 V-0 V-0 V-1 Non- (about 0.8standard mm thick) Tensile MPa 128 128 120 123 124 121 61 63 strengthHydrolysis resistance % 81 78 26 38 52 50 56 59 (tensile strengthretention rate) Tracking V 650 625 375 600 700 750 600 350 resistanceMetal pollution Rank 0 0 10 5 0 0 0 0 characteristic

TABLE 5 Compounding Example Example Example Example Example ExampleExample Example Example Composition amount 2 11 26 27 28 29 30 31 32<A-1> PBT % 27 27 26 26 26 26 26 27 27 <B-2> AS ″ 8 — 8 8 8 8 8 8 8<B-11> ″ — 8 — — — — — — — Multilayer structure <C-1> ″ 12 12 12 12 1212 12 12 12 Phosphoric acid ester <D-1> MC salt ″ 18 18 18 18 18 18 1818 18 <E-2> Calcium ″ 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 carbonate<G-1> GF ″ 34.5 34.5 33.5 33.5 33.5 33.5 33.5 34.3 34.3 <I-1> Silicone ″— — 2 — — — — — — <I-2> Phenol ″ — — — 2 — — — — — resin <I-3> ″ — — — —2 — — — — Phosphonitrile compound <J-1> Ethylene ″ — — — — — 2 — — —copolymer <K-1> Phenoxy ″ — — — — — — 2 — — resin <L-1> Hindered ″ — — —— — — — 0.2 0.1 phenol antioxidant <L-2> ″ — — — — — — — — 0.1 Phosphiteantioxidant Property Unit Flame Rank V-0 V-0 V-0 V-0 V-0 V-1 V-0 V-0 V-0retardancy (about 0.8 mm thick) Flame ″ Non- Non- V-1 V-1 V-1 Non- V-1Non- Non- retardancy stan- stan- stan- stan- stan- (about 0.4 dard darddard dard dard mm thick) Tensile MPa 131 123 123 121 122 120 122 132 130strength Hydrolysis % 58 51 51 50 52 50 63 58 56 resistance (tensilestrength retention rate) Tracking V 650 600 625 575 625 700 625 650 650resistance Metal Rank 0 0 0 0 0 0 0 0 0 pollution characteristic Izodimpact J/m 85 115 — — — 104 — — — Heat resistance % 42 41 — — — — — 6165 (tensile strength retention rate)

The cases of Comparative Example 1–Comparative Example 3 in Table 2where neither one of the (B) vinyl resin and the (E) alkaline earthmetal compound was compounded or one of them was not compounded wereinferior in hydrolysis resistance and metal pollution. ComparativeExample 1 and Comparative Example 3 where the (B) vinyl resin was notcompounded were also inferior in tracking resistance. From this, it hasbecome apparent that compositions made up of the (A) PBT, the (C)phosphoric acid ester and the (D) MC salt are compositions havingchallenges in hydrolysis resistance, metal pollution and trackingresistance.

Table 1 indicates effects of the compositions made up of components ofthe (A) PBT, the (B) vinyl resin, the (C) phosphoric acid ester, the (D)MC salt, and the (E) alkaline earth metal compound regarding flameretardancy, hydrolyzability, tracking resistance and metal pollutioncharacteristic.

From Example 1–Example 13 in Table 1, it can be said that thecompositions are excellent in flame retardancy, hydrolyzability,tracking resistance and metal pollution characteristic while maintaininghigh degree of flame retardancy, and solve the challenges of ComparativeExample 1–Comparative Example 3, and therefore have great effects.

Of Example 1–Example 9, Example 2–Example 4 where an AS containingacrylonitrile at 50 wt. % or less and 10 wt. % or greater was compoundedas the (B) vinyl resin were particularly excellent in hydrolysisresistance and metal pollution characteristic. Among them, Example 4where the epoxy-modified AS was compounded was particularly excellent inhydrolysis resistance.

Furthermore, from Example 10–Example 12, similar effects were seen inthe multilayer structures having the (B) vinyl resin in the shell layerof an outer layer. Among them, Example 11 having an AS in the shelllayer of an outer layer was particularly excellent in hydrolysisresistance and metal pollution characteristic.

Table 2 indicates the compounding amounts of the (B) vinyl resin, the(C) phosphoric acid ester and the (D) MC salt, and effects regardingflame retardancy, hydrolysis resistance, tracking resistance and metalpollution characteristic.

From Example 14 and Comparative Example 4, in the cases of a compoundingamount of the (B) vinyl resin exceeding 20%, the flame retardancy andthe hydrolysis resistance greatly deteriorated.

From Example 15 and Comparative Example 5, in the cases of a compoundingamount of the (C) phosphoric acid ester exceeding 20%, the hydrolysisresistance and the metal pollution characteristic greatly deteriorated.

From Example 16 and Comparative Example 6, the cases of a compoundingamount of the (D) MC salt exceeding 30% were inferior in the fluidityduring injection molding, so that a formed article of predetermineddimensions could not be obtained.

Table 3 indicates effects regarding flame retardancy, hydrolysisresistance, tracking resistance, and metal pollution characteristic, inrelation to the compounding amount of the (E) alkaline earth metalcompound, and the compounding ratio of the (C) phosphoric acid ester andthe (E) alkaline earth metal compound. Table 3 also indicates effectsregarding flame retardancy, hydrolysis resistance, tracking resistance,and metal pollution characteristic in the cases where PC, PPO or PPS wascompounded in place of the (B) vinyl resin.

From Example 17–Example 18 and Comparative Example 7–Comparative Example8, the compositions in which more than 5% of the (E) alkaline earthmetal compound was compounded had great deteriorations inhydrolyzability and metal pollution characteristic. Furthermore, fromExample 17–Example 20 and Comparative Example 7–Comparative Example 8,the compositions in which the compounding ratio of the (C) phosphoricacid ester and the (E) alkaline earth metal compound was within therange of the expression (5) exhibited more preferable hydrolyzabilityand metal pollution characteristic.

Calcium carbonate, etc., that is, an alkaline earth metal compoundcompounded, is generally compounded in plastics as an inorganic fillerin some cases for improving dimension stability, etc. However, thecompounding amount thereof in such cases is greater than 5%, and isordinarily 10–30% in many cases in order to bring about the effect as anordinary filler. That is, the amount thereof compounded as a generalinorganic filler does not have effects of the compositions herein. Bycompounding calcium carbonate in a compounding amount of 5% or less, andpreferably within the range of the expression (5), the hydrolyzabilityand metal pollution characteristic effects are realized.

Furthermore, from Comparative Example 9–Comparative Example 11, thecompositions in which PC, PPE or PPS was compounded in replace of the(B) vinyl resin were compositions excellent in flame retardancy butinferior in hydrolyzability, tracking resistance and metal pollutioncharacteristic. Therefore, it can be said that by compounding the (B)vinyl resin, the desired effects can be obtained.

Table 4 indicates the effect of the epoxy compound of (F), the effect ofthe case where a mixture of PBT and PET was used as the (A) component,and the effects regarding flame retardancy, hydrolysis resistance,tracking resistance and metal pollution characteristic with respect tothe compounding amount of the (A) component and the compositions ofnon-reinforced resin without glass fiber compounded.

From comparison of Example 21 and Example 22 with Example 2, thehydrolysis resistance was improved to a large extent by compounding theepoxy compound of (F) in the present invention composition. FromComparative Example 12 and Comparative Example 13, the cases where the(B) vinyl based resin and the (E) alkaline earth metal compound, or the(E) alkaline earth metal compound was not compounded resulted incompositions that were inferior in metal pollution characteristicbesides having a reduced effect regarding hydrolysis resistance.

From Example 23–Example 24, it can be said that, also in the cases wherea mixture of PBT and PET was used, compositions excellent in flameretardancy, hydrolysis resistance, tracking resistance and metalpollution characteristic can be obtained. Particularly, compared withthe composition of Example 2 without the PET mixed, the cases employingthe (A) mixture of PBT and PET obtained a tracking resistance exceeding700V, and therefore the cases employing the (A) mixture of PBT and PETcan be said to have an effect of further improving the trackingresistance.

However, in Comparative Example 14 employing only PET without any PBTmixed, the solidifying rate in the mold during injection molding wasslow, and a formed article of predetermined dimensions was not obtained.

From comparison of Example 25 and Comparative Example 15, it can be saidthat even with a non-reinforced resin without glass fiber compounded, acomposition excellent in flame retardancy, hydrolysis resistance,tracking resistance and metal pollution characteristic can be obtained.However, from Comparative Example 15, if the amount of the (A) componentexceeds 70%, the flame retardancy cannot be obtained.

Table 5 indicates the effects of flame retarding assistants, an ethylene(co)polymer, a hydrolysis resistance-improving agent and antioxidant.

From Example 26–Example 28, the compositions in which a flame retardingassistant of a silicone, a phenol resin or a phosphonitrile compound wasfurther compounded exhibited high degrees of flame retardancy whilemaintaining other properties even in their test pieces of about 0.4 mmin thickness.

From comparison of Example 29 with Example 2, the composition in whichan ethylene (co)polymer was further compounded exhibited a high impactstrength while maintaining other properties although the flameretardancy slightly deteriorated. The composition of Example 11 in whicha multilayer structure was further compounded as a (B) componentexhibited an even higher impact strength, and it can be said that thecompounding of a multilayer structure has an effect on improvement inimpact strength.

In Example 30, a phenoxy resin was compounded as a hydrolysisresistance-improving agent, and an effect on the hydrolysis resistancewas seen. However, the effect thereof is inferior, in comparison withthe epoxy compound of Example 21. Still, as a high degree of flameretardancy was obtained, it can be said to have a flame retardingassistant effect.

From comparison of Example 31–Example 32 with Example 2, thecompositions in which an antioxidant was further compounded exhibitedhigh heat resistances while maintaining other properties, and a morepreferable result was obtained in the case where the hindered phenolantioxidant and the phosphite antioxidant were both employed.

INDUSTRIAL APPLICABILITY

The formed article made of the flame-retardant polybutyleneterephthalate resin composition employs a non-halogenated flameretardant considered to have less influence on the environment, and hassafety from the electrical burning inside instruments, and high degreeof flame retardancy against the burning of the formed article itself, sothat it is useful for electrical/electronic component parts, machinemechanism component parts, and automotive component parts. Specifically,breakers, electromagnetic switches, focus cases, flyback transformer,formed articles for fusers of printers and copiers, general householdelectrical appliances, housings of OA machines, etc., coil bobbins,connectors, relays, disc drive chassis, transformers, switch componentparts, convenience outlet component parts, electric motor componentparts, sockets, plugs, capacitors, various cases, etc., resistors,electrical/electronic component parts in which metallic terminals orleads are incorporated, computer-related component parts, acousticcomponent parts, audio component parts such as laser discs, illuminationcomponent parts, telegraph/telephone instrument-related component parts,airconditioner component parts, component parts of home appliances, suchas VTRs, televisions, etc., component parts for copiers, component partsfor facsimiles, component parts for optical instruments, automotiveignition device component parts, connectors for motor vehicles, andvarious electrical equipment component parts for motor vehicles, etc.may be cited.

Since highly reliable formed articles having excellent performancesparticularly with respect to flame retardancy, hydrolyzability and metalpollution are obtained, the compositions are especially useful forelectrical/electronic component parts, such as relays, breakers,electromagnetic switches, focus cases, flyback transformers, formedarticles for fusers of copiers and printers, etc.

Furthermore, with regard to formed articles used in high voltagemodification or component parts that receives high voltage, a trackingphenomenon in which carbonization progresses and results in ignition isapprehended. However, since formed articles having a performance of 400Vor greater in relative tracking index are obtained, the articles areespecially useful as breakers, electromagnetic switches, and formedarticles for fusers of printers and copiers mentioned above.

1. A flame-retardant polybutylene terephthalate resin compositionwherein (A) 20–70% by weight of a polybutylene terephthalate resin or amixture of a polybutylene terephthalate resin and a polyethyleneterephthalate resin, (B) 1–20% by weight of an acrylonitrile/styrenecopolymer containing acrylonitrile at 10 wt % or greater and less than50 wt %, (C) 1–20% by weight of a phosphoric acid ester, (D) 1–30% byweight of a salt of a triazine based compound and cyanuric acid orisocyanuric acid, and (E) 0.1–5% by weight of magnesium hydroxide and/orcalcium carbonate.
 2. A flame-retardant polybutylene terephthalate resincomposition according to claim 1, wherein the polybutylenetereplithalate resin constituting the mixture of the polybutylenetereplithalate resin and the polyethylene terephthalate resin is at5–95% by weight, and the polyethylene terephthalate resin is at 95–5% byweight.
 3. A flame-retardant polybutylene terephthalate resincomposition according to claim 1, wherein (F) 0.05–5% by weight of anepoxy compound is compounded.
 4. A flame-retardant polybutyleneterephthalate resin composition according to claim 3, wherein the (F)epoxy compound is an epoxy compound including a glycidyl ether compoundand/or a glycidyl ester compound having an epoxy equivalent of 500 orless.
 5. A flame-retardant polybutylene terephthalate resin compositionaccording to claim 3, wherein the (F) epoxy compound is an epoxycompound including a monofunctional glycidyl ester compound having anepoxy equivalent of 500 or less.
 6. A flame-retardant polybutyleneterephthalate resin composition according to claim 1, wherein the (C)phosphoric acid ester is an aromatic phosphoric acid ester representedby the following (1) expression:

wherein Ar¹, Ar², Ar³ and Ar⁴ represent the same or different aromaticgroups that do not contain a halogen; X represents a structure selectedfrom expressions (2)–(4):

wherein R¹ to R⁸ represent the same or different hydrogen atoms or alkylgroups having carbon numbers of 1–5, Y represents a direct coupling, O,S, SO₂, C(CH₃)₂, CH₂, CHPh, and Ph represents a phenyl group; n in the(1) expression represents the degree of polymerization, and is aninteger of 0 or greater, k, m in the (1) expression are each an integerof 0 or greater and 2 or less, and (k+m) is an integer of 0 or greaterand 2 or less.
 7. A flame-retardant polybutylene terephthalate resincomposition according to claim 1, wherein the (B) acrylonitrile/styrenecopolymer is copolymerized with a glycidyl methacrylate.
 8. Aflame-retardant polybutylene terephthalate resin composition accordingto claim 1, wherein the (B) acrylonitrile/styrene is a multilayerstructure that constitutes an outer layer (shell layer) of a multilayerstructure made up of an innermost layer (core layer) and the outer layer(shell layer) covering the innermost layer.
 9. A flame-retardantpolybutylene terephthalate resin composition according to claim 1,wherein the compounding ratio of the (C) phosphoric acid ester and the(E) magnesium hydroxide and/or calcium carbonate is within a range ofthe following expression (5): $\begin{matrix}{{\frac{Wp}{M} \times {Np} \times 0.03} \leqq {\frac{Wa}{Ma} \times 2} \leqq {\frac{Wp}{M} \times {Np} \times 0.6}} & (5)\end{matrix}$ wherein W_(p) is the compounding amount (% by weight) ofthe (C) phosphoric acid ester, and M is the molecular weight of the (C)phosphoric acid ester, and N_(p) is the number of phosphoric acid esterlinkages of the (C) phosphoric acid ester, and Wa is the compoundingamount (% by weight) of the (E) magnesium hydroxide and/or calciumcarbonate, and Ma is the molecular weight of the (E) magnesium hydroxideand/or calcium carbonate.
 10. A flame-retardant polybutyleneterephthalate resin composition according to claim 1, having a relativetracking index of 400V or greater.
 11. A formed article formed from aflame-retardant polybutylene terephthalate resin composition accordingto claim 1, wherein the article is a machine mechanism component part,an electrical/electronic component part, or an automotive componentpart.
 12. A formed article formed from a flame-retardant polybutyleneterephthalate resin composition according to claim 1, wherein thearticle is a breaker, an electromagnetic switch, a focus case, a flybacktransformer, or a fuser of a copier or a printer.